diff --git a/OpenRA.Game/Support/BooleanExpression.cs b/OpenRA.Game/Support/BooleanExpression.cs
index c11d35ab02..a31b9aa402 100644
--- a/OpenRA.Game/Support/BooleanExpression.cs
+++ b/OpenRA.Game/Support/BooleanExpression.cs
@@ -222,7 +222,7 @@ namespace OpenRA.Support
 			return new VariableToken(start, expression.Substring(start));
 		}
 
-		static bool ParseSymbol(VariableToken t, Dictionary<string, bool> symbols)
+		static bool ParseSymbol(VariableToken t, IReadOnlyDictionary<string, bool> symbols)
 		{
 			bool value;
 			symbols.TryGetValue(t.Symbol, out value);
@@ -271,7 +271,7 @@ namespace OpenRA.Support
 				yield return s.Pop();
 		}
 
-		public bool Evaluate(Dictionary<string, bool> symbols)
+		public bool Evaluate(IReadOnlyDictionary<string, bool> symbols)
 		{
 			var s = new Stack<bool>();
 			foreach (var t in postfix)
diff --git a/OpenRA.Mods.Common/Traits/Armament.cs b/OpenRA.Mods.Common/Traits/Armament.cs
index 53423f4e25..06f493fc13 100644
--- a/OpenRA.Mods.Common/Traits/Armament.cs
+++ b/OpenRA.Mods.Common/Traits/Armament.cs
@@ -96,7 +96,7 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class Armament : UpgradableTrait<ArmamentInfo>, INotifyCreated, ITick, IExplodeModifier
+	public class Armament : UpgradableTrait<ArmamentInfo>, ITick, IExplodeModifier
 	{
 		public readonly WeaponInfo Weapon;
 		public readonly Barrel[] Barrels;
@@ -141,12 +141,14 @@ namespace OpenRA.Mods.Common.Traits
 			return new WDist(Util.ApplyPercentageModifiers(Weapon.Range.Length, rangeModifiers));
 		}
 
-		protected virtual void Created(Actor self)
+		protected override void Created(Actor self)
 		{
 			turret = self.TraitsImplementing<Turreted>().FirstOrDefault(t => t.Name == Info.Turret);
 			ammoPool = self.TraitsImplementing<AmmoPool>().FirstOrDefault(la => la.Info.Name == Info.AmmoPoolName);
 			coords = self.Trait<BodyOrientation>();
 			rangeModifiers = self.TraitsImplementing<IRangeModifier>().ToArray().Select(m => m.GetRangeModifier());
+
+			base.Created(self);
 		}
 
 		protected virtual void Tick(Actor self)
@@ -170,12 +172,6 @@ namespace OpenRA.Mods.Common.Traits
 			delayedActions.RemoveAll(a => a.First <= 0);
 		}
 
-		void INotifyCreated.Created(Actor self)
-		{
-			// Split into a protected method to allow subclassing
-			Created(self);
-		}
-
 		void ITick.Tick(Actor self)
 		{
 			// Split into a protected method to allow subclassing
diff --git a/OpenRA.Mods.Common/Traits/Cargo.cs b/OpenRA.Mods.Common/Traits/Cargo.cs
index 5e66f98e38..0ce4b9b853 100644
--- a/OpenRA.Mods.Common/Traits/Cargo.cs
+++ b/OpenRA.Mods.Common/Traits/Cargo.cs
@@ -20,7 +20,7 @@ using OpenRA.Traits;
 namespace OpenRA.Mods.Common.Traits
 {
 	[Desc("This actor can transport Passenger actors.")]
-	public class CargoInfo : ITraitInfo, Requires<IOccupySpaceInfo>, Requires<UpgradeManagerInfo>
+	public class CargoInfo : ITraitInfo, Requires<IOccupySpaceInfo>
 	{
 		[Desc("The maximum sum of Passenger.Weight that this actor can support.")]
 		public readonly int MaxWeight = 0;
@@ -67,7 +67,6 @@ namespace OpenRA.Mods.Common.Traits
 	{
 		public readonly CargoInfo Info;
 		readonly Actor self;
-		readonly UpgradeManager upgradeManager;
 		readonly Stack<Actor> cargo = new Stack<Actor>();
 		readonly HashSet<Actor> reserves = new HashSet<Actor>();
 		readonly Lazy<IFacing> facing;
@@ -76,6 +75,7 @@ namespace OpenRA.Mods.Common.Traits
 		int totalWeight = 0;
 		int reservedWeight = 0;
 		Aircraft aircraft;
+		UpgradeManager upgradeManager;
 
 		CPos currentCell;
 		public IEnumerable<CPos> CurrentAdjacentCells { get; private set; }
@@ -89,7 +89,6 @@ namespace OpenRA.Mods.Common.Traits
 			Info = info;
 			Unloading = false;
 			checkTerrainType = info.UnloadTerrainTypes.Count > 0;
-			upgradeManager = self.Trait<UpgradeManager>();
 
 			if (init.Contains<RuntimeCargoInit>())
 			{
@@ -127,6 +126,7 @@ namespace OpenRA.Mods.Common.Traits
 		void INotifyCreated.Created(Actor self)
 		{
 			aircraft = self.TraitOrDefault<Aircraft>();
+			upgradeManager = self.Trait<UpgradeManager>();
 		}
 
 		static int GetWeight(Actor a) { return a.Info.TraitInfo<PassengerInfo>().Weight; }
diff --git a/OpenRA.Mods.Common/Traits/Carryable.cs b/OpenRA.Mods.Common/Traits/Carryable.cs
index ba26914040..7674266188 100644
--- a/OpenRA.Mods.Common/Traits/Carryable.cs
+++ b/OpenRA.Mods.Common/Traits/Carryable.cs
@@ -15,7 +15,7 @@ using OpenRA.Traits;
 namespace OpenRA.Mods.Common.Traits
 {
 	[Desc("Can be carried by actors with the `Carryall` trait.")]
-	public class CarryableInfo : ITraitInfo, Requires<UpgradeManagerInfo>
+	public class CarryableInfo : ITraitInfo
 	{
 		[UpgradeGrantedReference]
 		[Desc("The upgrades to grant to self while waiting or being carried.")]
@@ -27,10 +27,10 @@ namespace OpenRA.Mods.Common.Traits
 		public virtual object Create(ActorInitializer init) { return new Carryable(init.Self, this); }
 	}
 
-	public class Carryable
+	public class Carryable : INotifyCreated
 	{
 		readonly CarryableInfo info;
-		readonly UpgradeManager upgradeManager;
+		UpgradeManager upgradeManager;
 
 		public Actor Carrier { get; private set; }
 		public bool Reserved { get { return state != State.Free; } }
@@ -44,6 +44,10 @@ namespace OpenRA.Mods.Common.Traits
 		public Carryable(Actor self, CarryableInfo info)
 		{
 			this.info = info;
+		}
+
+		void INotifyCreated.Created(Actor self)
+		{
 			upgradeManager = self.Trait<UpgradeManager>();
 		}
 
diff --git a/OpenRA.Mods.Common/Traits/KillsSelf.cs b/OpenRA.Mods.Common/Traits/KillsSelf.cs
index 1411d8364f..65365028a5 100644
--- a/OpenRA.Mods.Common/Traits/KillsSelf.cs
+++ b/OpenRA.Mods.Common/Traits/KillsSelf.cs
@@ -29,10 +29,10 @@ namespace OpenRA.Mods.Common.Traits
 		public void AddedToWorld(Actor self)
 		{
 			if (!IsTraitDisabled)
-				UpgradeEnabled(self);
+				TraitEnabled(self);
 		}
 
-		protected override void UpgradeEnabled(Actor self)
+		protected override void TraitEnabled(Actor self)
 		{
 			if (self.IsDead)
 				return;
diff --git a/OpenRA.Mods.Common/Traits/Multipliers/PowerMultiplier.cs b/OpenRA.Mods.Common/Traits/Multipliers/PowerMultiplier.cs
index dee64dba15..68d493b6bb 100644
--- a/OpenRA.Mods.Common/Traits/Multipliers/PowerMultiplier.cs
+++ b/OpenRA.Mods.Common/Traits/Multipliers/PowerMultiplier.cs
@@ -33,8 +33,8 @@ namespace OpenRA.Mods.Common.Traits
 			power = self.Owner.PlayerActor.Trait<PowerManager>();
 		}
 
-		protected override void UpgradeEnabled(Actor self) { power.UpdateActor(self); }
-		protected override void UpgradeDisabled(Actor self) { power.UpdateActor(self); }
+		protected override void TraitEnabled(Actor self) { power.UpdateActor(self); }
+		protected override void TraitDisabled(Actor self) { power.UpdateActor(self); }
 
 		int IPowerModifier.GetPowerModifier() { return IsTraitDisabled ? 100 : Info.Modifier; }
 
diff --git a/OpenRA.Mods.Common/Traits/Power/CanPowerDown.cs b/OpenRA.Mods.Common/Traits/Power/CanPowerDown.cs
index 0cbb9d9ef9..6b5953a3b8 100644
--- a/OpenRA.Mods.Common/Traits/Power/CanPowerDown.cs
+++ b/OpenRA.Mods.Common/Traits/Power/CanPowerDown.cs
@@ -82,7 +82,7 @@ namespace OpenRA.Mods.Common.Traits
 			power = newOwner.PlayerActor.Trait<PowerManager>();
 		}
 
-		protected override void UpgradeDisabled(Actor self)
+		protected override void TraitDisabled(Actor self)
 		{
 			if (!disabled || !Info.CancelWhenDisabled)
 				return;
diff --git a/OpenRA.Mods.Common/Traits/Power/Power.cs b/OpenRA.Mods.Common/Traits/Power/Power.cs
index 839165a668..148d614bc1 100644
--- a/OpenRA.Mods.Common/Traits/Power/Power.cs
+++ b/OpenRA.Mods.Common/Traits/Power/Power.cs
@@ -41,8 +41,8 @@ namespace OpenRA.Mods.Common.Traits
 			powerModifiers = Exts.Lazy(() => self.TraitsImplementing<IPowerModifier>().ToArray());
 		}
 
-		protected override void UpgradeEnabled(Actor self) { PlayerPower.UpdateActor(self); }
-		protected override void UpgradeDisabled(Actor self) { PlayerPower.UpdateActor(self); }
+		protected override void TraitEnabled(Actor self) { PlayerPower.UpdateActor(self); }
+		protected override void TraitDisabled(Actor self) { PlayerPower.UpdateActor(self); }
 		public void AddedToWorld(Actor self) { PlayerPower.UpdateActor(self); }
 		public void RemovedFromWorld(Actor self) { PlayerPower.RemoveActor(self); }
 		public void OnOwnerChanged(Actor self, Player oldOwner, Player newOwner)
diff --git a/OpenRA.Mods.Common/Traits/Render/LeavesTrails.cs b/OpenRA.Mods.Common/Traits/Render/LeavesTrails.cs
index 824ecfb9ba..8fc813c2de 100644
--- a/OpenRA.Mods.Common/Traits/Render/LeavesTrails.cs
+++ b/OpenRA.Mods.Common/Traits/Render/LeavesTrails.cs
@@ -61,7 +61,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 		public override object Create(ActorInitializer init) { return new LeavesTrails(init.Self, this); }
 	}
 
-	public class LeavesTrails : UpgradableTrait<LeavesTrailsInfo>, ITick, INotifyCreated
+	public class LeavesTrails : UpgradableTrait<LeavesTrailsInfo>, ITick
 	{
 		BodyOrientation body;
 		IFacing facing;
@@ -75,12 +75,14 @@ namespace OpenRA.Mods.Common.Traits.Render
 		}
 
 		WPos cachedPosition;
-		public void Created(Actor self)
+		protected override void Created(Actor self)
 		{
 			body = self.Trait<BodyOrientation>();
 			facing = self.TraitOrDefault<IFacing>();
 			cachedFacing = facing != null ? facing.Facing : 0;
 			cachedPosition = self.CenterPosition;
+
+			base.Created(self);
 		}
 
 		int ticks;
@@ -132,7 +134,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 			}
 		}
 
-		protected override void UpgradeEnabled(Actor self)
+		protected override void TraitEnabled(Actor self)
 		{
 			cachedPosition = self.CenterPosition;
 		}
diff --git a/OpenRA.Mods.Common/Traits/Render/WithInfantryBody.cs b/OpenRA.Mods.Common/Traits/Render/WithInfantryBody.cs
index f862814e4d..ad1eaa0195 100644
--- a/OpenRA.Mods.Common/Traits/Render/WithInfantryBody.cs
+++ b/OpenRA.Mods.Common/Traits/Render/WithInfantryBody.cs
@@ -52,7 +52,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 		}
 	}
 
-	public class WithInfantryBody : UpgradableTrait<WithInfantryBodyInfo>, ITick, INotifyAttack, INotifyIdle, INotifyCreated
+	public class WithInfantryBody : UpgradableTrait<WithInfantryBodyInfo>, ITick, INotifyAttack, INotifyIdle
 	{
 		readonly IMove move;
 		protected readonly Animation DefaultAnimation;
@@ -90,9 +90,11 @@ namespace OpenRA.Mods.Common.Traits.Render
 			}
 		}
 
-		public void Created(Actor self)
+		protected override void Created(Actor self)
 		{
 			rsm = self.TraitOrDefault<IRenderInfantrySequenceModifier>();
+
+			base.Created(self);
 		}
 
 		protected virtual string NormalizeInfantrySequence(Actor self, string baseSequence)
diff --git a/OpenRA.Mods.Common/Traits/Render/WithParachute.cs b/OpenRA.Mods.Common/Traits/Render/WithParachute.cs
index 08e8095ddd..aa3692950b 100644
--- a/OpenRA.Mods.Common/Traits/Render/WithParachute.cs
+++ b/OpenRA.Mods.Common/Traits/Render/WithParachute.cs
@@ -128,7 +128,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 			rs.Add(anim, info.Palette, info.IsPlayerPalette);
 		}
 
-		protected override void UpgradeEnabled(Actor self)
+		protected override void TraitEnabled(Actor self)
 		{
 			if (info.Image == null)
 				return;
@@ -136,7 +136,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 			anim.Animation.PlayThen(info.OpeningSequence, () => anim.Animation.PlayRepeating(info.Sequence));
 		}
 
-		protected override void UpgradeDisabled(Actor self)
+		protected override void TraitDisabled(Actor self)
 		{
 			if (info.Image == null)
 				return;
diff --git a/OpenRA.Mods.Common/Traits/Targetable.cs b/OpenRA.Mods.Common/Traits/Targetable.cs
index a955e23ba0..11a32908ee 100644
--- a/OpenRA.Mods.Common/Traits/Targetable.cs
+++ b/OpenRA.Mods.Common/Traits/Targetable.cs
@@ -27,7 +27,7 @@ namespace OpenRA.Mods.Common.Traits
 		public override object Create(ActorInitializer init) { return new Targetable(init.Self, this); }
 	}
 
-	public class Targetable : UpgradableTrait<TargetableInfo>, ITargetable, INotifyCreated
+	public class Targetable : UpgradableTrait<TargetableInfo>, ITargetable
 	{
 		protected static readonly string[] None = new string[] { };
 		protected Cloak[] cloaks;
@@ -35,9 +35,11 @@ namespace OpenRA.Mods.Common.Traits
 		public Targetable(Actor self, TargetableInfo info)
 			: base(info) { }
 
-		void INotifyCreated.Created(Actor self)
+		protected override void Created(Actor self)
 		{
 			cloaks = self.TraitsImplementing<Cloak>().ToArray();
+
+			base.Created(self);
 		}
 
 		public virtual bool TargetableBy(Actor self, Actor viewer)
diff --git a/OpenRA.Mods.Common/Traits/Upgrades/UpgradableTrait.cs b/OpenRA.Mods.Common/Traits/Upgrades/UpgradableTrait.cs
index 843d3d98ef..527679875f 100644
--- a/OpenRA.Mods.Common/Traits/Upgrades/UpgradableTrait.cs
+++ b/OpenRA.Mods.Common/Traits/Upgrades/UpgradableTrait.cs
@@ -17,9 +17,9 @@ using OpenRA.Traits;
 namespace OpenRA.Mods.Common.Traits
 {
 	/// <summary>Use as base class for *Info to subclass of UpgradableTrait. (See UpgradableTrait.)</summary>
-	public abstract class UpgradableTraitInfo : IUpgradableInfo, IRulesetLoaded
+	public abstract class UpgradableTraitInfo : IConditionConsumerInfo, IRulesetLoaded
 	{
-		static readonly Dictionary<string, bool> NoConditions = new Dictionary<string, bool>();
+		static readonly IReadOnlyDictionary<string, bool> NoConditions = new ReadOnlyDictionary<string, bool>(new Dictionary<string, bool>());
 
 		[UpgradeUsedReference]
 		[Desc("Boolean expression defining the condition to enable this trait.")]
@@ -43,12 +43,11 @@ namespace OpenRA.Mods.Common.Traits
 	/// Requires basing *Info on UpgradableTraitInfo and using base(info) constructor.
 	/// Note that EnabledByUpgrade is not called at creation even if this starts as enabled.
 	/// </summary>
-	public abstract class UpgradableTrait<InfoType> : IUpgradable, IDisabledTrait, ISync where InfoType : UpgradableTraitInfo
+	public abstract class UpgradableTrait<InfoType> : IConditionConsumer, IDisabledTrait, INotifyCreated, ISync where InfoType : UpgradableTraitInfo
 	{
 		public readonly InfoType Info;
-		readonly Dictionary<string, bool> conditions = new Dictionary<string, bool>();
 
-		IEnumerable<string> IUpgradable.UpgradeTypes
+		IEnumerable<string> IConditionConsumer.Conditions
 		{
 			get
 			{
@@ -65,36 +64,38 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			Info = info;
 
-			// TODO: Set initial state from a ConditionsInit once that exists
-			IsTraitDisabled = info.RequiresCondition != null ?
-				!info.RequiresCondition.Evaluate(conditions) : false;
+			// Conditional traits will be enabled (if appropriate) by the UpgradeManager
+			// calling IConditionConsumer.ConditionsChanged at the end of INotifyCreated.
+			IsTraitDisabled = Info.RequiresCondition != null;
 		}
 
-		bool IUpgradable.AcceptsUpgradeLevel(Actor self, string type, int level)
+		protected virtual void Created(Actor self)
 		{
-			return level == 1;
+			if (Info.RequiresCondition == null)
+				TraitEnabled(self);
 		}
 
-		void IUpgradable.UpgradeLevelChanged(Actor self, string type, int oldLevel, int newLevel)
+		void INotifyCreated.Created(Actor self) { Created(self); }
+
+		void IConditionConsumer.ConditionsChanged(Actor self, IReadOnlyDictionary<string, bool> conditions)
 		{
+			if (Info.RequiresCondition == null)
+				return;
+
 			var wasDisabled = IsTraitDisabled;
-			conditions[type] = newLevel > 0;
 			IsTraitDisabled = !Info.RequiresCondition.Evaluate(conditions);
 
-			UpgradeLevelChanged(self, oldLevel, newLevel);
-
 			if (IsTraitDisabled != wasDisabled)
 			{
 				if (wasDisabled)
-					UpgradeEnabled(self);
+					TraitEnabled(self);
 				else
-					UpgradeDisabled(self);
+					TraitDisabled(self);
 			}
 		}
 
-		// Subclasses can add upgrade support by querying IsTraitDisabled and/or overriding these methods.
-		protected virtual void UpgradeLevelChanged(Actor self, int oldLevel, int newLevel) { }
-		protected virtual void UpgradeEnabled(Actor self) { }
-		protected virtual void UpgradeDisabled(Actor self) { }
+		// Subclasses can add condition support by querying IsTraitDisabled and/or overriding these methods.
+		protected virtual void TraitEnabled(Actor self) { }
+		protected virtual void TraitDisabled(Actor self) { }
 	}
 }
diff --git a/OpenRA.Mods.Common/Traits/Upgrades/UpgradeManager.cs b/OpenRA.Mods.Common/Traits/Upgrades/UpgradeManager.cs
index 81d2e0e4ad..d7a07ef96e 100644
--- a/OpenRA.Mods.Common/Traits/Upgrades/UpgradeManager.cs
+++ b/OpenRA.Mods.Common/Traits/Upgrades/UpgradeManager.cs
@@ -12,49 +12,44 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using OpenRA.Primitives;
 using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.Traits
 {
 	[Desc("Attach this to a unit to enable dynamic upgrades by warheads, experience, crates, support powers, etc.")]
-	public class UpgradeManagerInfo : TraitInfo<UpgradeManager>, IRulesetLoaded
-	{
-		public void RulesetLoaded(Ruleset rules, ActorInfo info)
-		{
-			if (!info.Name.StartsWith("^") && !info.TraitInfos<IUpgradableInfo>().Any())
-				throw new YamlException(
-					"There are no upgrades to be managed for actor '{0}'. You are either missing some upgradeable traits, or this UpgradeManager trait is not required.".F(
-						info.Name));
-		}
-	}
+	public class UpgradeManagerInfo : TraitInfo<UpgradeManager>, Requires<IConditionConsumerInfo> { }
 
 	public class UpgradeManager : INotifyCreated, ITick
 	{
-		class TimedUpgrade
+		/// <summary>Value used to represent an invalid token.</summary>
+		public static readonly int InvalidConditionToken = -1;
+
+		class TimedCondition
 		{
-			public class UpgradeSource
+			public class ConditionSource
 			{
 				public readonly object Source;
 				public int Remaining;
 
-				public UpgradeSource(int duration, object source)
+				public ConditionSource(int duration, object source)
 				{
 					Remaining = duration;
 					Source = source;
 				}
 			}
 
-			public readonly string Upgrade;
+			public readonly string Condition;
 			public readonly int Duration;
-			public readonly HashSet<UpgradeSource> Sources;
+			public readonly HashSet<ConditionSource> Sources;
 			public int Remaining; // Equal to maximum of all Sources.Remaining
 
-			public TimedUpgrade(string upgrade, int duration, object source)
+			public TimedCondition(string condition, int duration, object source)
 			{
-				Upgrade = upgrade;
+				Condition = condition;
 				Duration = duration;
 				Remaining = duration;
-				Sources = new HashSet<UpgradeSource> { new UpgradeSource(duration, source) };
+				Sources = new HashSet<ConditionSource> { new ConditionSource(duration, source) };
 			}
 
 			public void Tick()
@@ -65,29 +60,124 @@ namespace OpenRA.Mods.Common.Traits
 			}
 		}
 
-		class UpgradeState
+		class ConditionState
 		{
-			public readonly List<IUpgradable> Traits = new List<IUpgradable>();
-			public readonly List<object> Sources = new List<object>();
+			/// <summary>Traits that have registered to be notified when this condition changes.</summary>
+			public readonly List<IConditionConsumer> Consumers = new List<IConditionConsumer>();
+
+			/// <summary>Unique integers identifying granted instances of the condition.</summary>
+			public readonly HashSet<int> Tokens = new HashSet<int>();
+
+			/// <summary>External callbacks that are to be executed when a timed condition changes.</summary>
 			public readonly List<Action<int, int>> Watchers = new List<Action<int, int>>();
 		}
 
-		readonly List<TimedUpgrade> timedUpgrades = new List<TimedUpgrade>();
-		readonly Dictionary<IUpgradable, int> levels = new Dictionary<IUpgradable, int>();
-		Dictionary<string, UpgradeState> upgrades;
+		readonly List<TimedCondition> timedConditions = new List<TimedCondition>();
+
+		Dictionary<string, ConditionState> state;
+
+		/// <summary>Each granted condition receives a unique token that is used when revoking.</summary>
+		Dictionary<int, string> tokens = new Dictionary<int, string>();
+
+		int nextToken = 1;
+
+		/// <summary>Temporary shim between the old and new upgrade/condition grant and revoke methods.</summary>
+		Dictionary<Pair<object, string>, int> objectTokenShim = new Dictionary<Pair<object, string>, int>();
+
+		/// <summary>Cache of condition -> enabled state for quick evaluation of boolean conditions.</summary>
+		Dictionary<string, bool> conditionCache = new Dictionary<string, bool>();
+
+		/// <summary>Read-only version of conditionCache that is passed to IConditionConsumers.</summary>
+		IReadOnlyDictionary<string, bool> readOnlyConditionCache;
 
 		void INotifyCreated.Created(Actor self)
 		{
-			upgrades = new Dictionary<string, UpgradeState>();
-			foreach (var up in self.TraitsImplementing<IUpgradable>())
-				foreach (var t in up.UpgradeTypes)
-					upgrades.GetOrAdd(t).Traits.Add(up);
+			state = new Dictionary<string, ConditionState>();
+			readOnlyConditionCache = new ReadOnlyDictionary<string, bool>(conditionCache);
+
+			var allConsumers = new HashSet<IConditionConsumer>();
+			foreach (var consumer in self.TraitsImplementing<IConditionConsumer>())
+			{
+				allConsumers.Add(consumer);
+				foreach (var condition in consumer.Conditions)
+				{
+					state.GetOrAdd(condition).Consumers.Add(consumer);
+					conditionCache[condition] = false;
+				}
+			}
+
+			// Enable any conditions granted during trait setup
+			foreach (var kv in tokens)
+			{
+				ConditionState conditionState;
+				if (!state.TryGetValue(kv.Value, out conditionState))
+					continue;
+
+				conditionState.Tokens.Add(kv.Key);
+				conditionCache[kv.Value] = conditionState.Tokens.Count > 0;
+			}
+
+			// Update all traits with their initial condition state
+			foreach (var consumer in allConsumers)
+				consumer.ConditionsChanged(self, readOnlyConditionCache);
 		}
 
-		void CheckCanManageUpgrades()
+		void UpdateConditionState(Actor self, string condition, int token, bool isRevoke)
 		{
-			if (upgrades == null)
-				throw new InvalidOperationException("Upgrades cannot be managed until the actor has been fully created.");
+			ConditionState conditionState;
+			if (!state.TryGetValue(condition, out conditionState))
+				return;
+
+			if (isRevoke)
+				conditionState.Tokens.Remove(token);
+			else
+				conditionState.Tokens.Add(token);
+
+			conditionCache[condition] = conditionState.Tokens.Count > 0;
+
+			foreach (var t in conditionState.Consumers)
+				t.ConditionsChanged(self, readOnlyConditionCache);
+		}
+
+		/// <summary>Grants a specified condition.</summary>
+		/// <returns>The token that is used to revoke this condition.</returns>
+		public int GrantCondition(Actor self, string condition)
+		{
+			var token = nextToken++;
+			tokens.Add(token, condition);
+
+			// Conditions may be granted before the state is initialized.
+			// These conditions will be processed in INotifyCreated.Created.
+			if (state != null)
+				UpdateConditionState(self, condition, token, false);
+
+			return token;
+		}
+
+		/// <summary>Revokes a previously granted condition.</summary>
+		/// <returns>The invalid token ID</returns>
+		/// <param name="token">The token ID returned by GrantCondition.</param>
+		public int RevokeCondition(Actor self, int token)
+		{
+			string condition;
+			if (!tokens.TryGetValue(token, out condition))
+				throw new InvalidOperationException("Attempting to revoke condition with invalid token {0} for {1}.".F(token, self));
+
+			tokens.Remove(token);
+
+			// Conditions may be granted and revoked before the state is initialized.
+			if (state != null)
+				UpdateConditionState(self, condition, token, true);
+
+			return InvalidConditionToken;
+		}
+
+		#region Shim methods for legacy upgrade granting code
+
+		void CheckCanManageConditions()
+		{
+			if (state == null)
+				throw new InvalidOperationException("Conditions cannot be managed until the actor has been fully created.");
 		}
 
 		/// <summary>Upgrade level increments are limited to dupesAllowed per source, i.e., if a single
@@ -98,11 +188,11 @@ namespace OpenRA.Mods.Common.Traits
 		/// remaining upgrade duration will be replaced by the new source.</summary>
 		public void GrantTimedUpgrade(Actor self, string upgrade, int duration, object source = null, int dupesAllowed = 1)
 		{
-			var timed = timedUpgrades.FirstOrDefault(u => u.Upgrade == upgrade);
+			var timed = timedConditions.FirstOrDefault(u => u.Condition == upgrade);
 			if (timed == null)
 			{
-				timed = new TimedUpgrade(upgrade, duration, source);
-				timedUpgrades.Add(timed);
+				timed = new TimedCondition(upgrade, duration, source);
+				timedConditions.Add(timed);
 				GrantUpgrade(self, upgrade, timed);
 				return;
 			}
@@ -110,7 +200,7 @@ namespace OpenRA.Mods.Common.Traits
 			var srcs = timed.Sources.Where(s => s.Source == source);
 			if (srcs.Count() < dupesAllowed)
 			{
-				timed.Sources.Add(new TimedUpgrade.UpgradeSource(duration, source));
+				timed.Sources.Add(new TimedCondition.ConditionSource(duration, source));
 				if (AcceptsUpgrade(self, upgrade))
 					GrantUpgrade(self, upgrade, timed);
 				else
@@ -122,108 +212,69 @@ namespace OpenRA.Mods.Common.Traits
 			timed.Remaining = Math.Max(duration, timed.Remaining);
 		}
 
-		// Different upgradeable traits may define (a) different level ranges for the same upgrade type,
-		// and (b) multiple upgrade types for the same trait. The unrestricted level for each trait is
-		// tracked independently so that we can correctly revoke levels without adding the burden of
-		// tracking both the overall (unclamped) and effective (clamped) levels on each individual trait.
-		void NotifyUpgradeLevelChanged(IEnumerable<IUpgradable> traits, Actor self, string upgrade, int levelAdjust)
-		{
-			foreach (var up in traits)
-			{
-				var oldLevel = levels.GetOrAdd(up);
-				var newLevel = levels[up] = oldLevel + levelAdjust;
-
-				// This will internally clamp the levels to its own restricted range
-				up.UpgradeLevelChanged(self, upgrade, oldLevel, newLevel);
-			}
-		}
-
-		int GetOverallLevel(IUpgradable upgradable)
-		{
-			int level;
-			return levels.TryGetValue(upgradable, out level) ? level : 0;
-		}
-
 		public void GrantUpgrade(Actor self, string upgrade, object source)
 		{
-			CheckCanManageUpgrades();
-
-			UpgradeState s;
-			if (!upgrades.TryGetValue(upgrade, out s))
-				return;
-
-			// Track the upgrade source so that the upgrade can be removed without conflicts
-			s.Sources.Add(source);
-
-			NotifyUpgradeLevelChanged(s.Traits, self, upgrade, 1);
+			CheckCanManageConditions();
+			objectTokenShim[Pair.New(source, upgrade)] = GrantCondition(self, upgrade);
 		}
 
 		public void RevokeUpgrade(Actor self, string upgrade, object source)
 		{
-			CheckCanManageUpgrades();
-
-			UpgradeState s;
-			if (!upgrades.TryGetValue(upgrade, out s))
-				return;
-
-			if (!s.Sources.Remove(source))
-				throw new InvalidOperationException("Object <{0}> revoked more levels of upgrade {1} than it granted for {2}.".F(source, upgrade, self));
-
-			NotifyUpgradeLevelChanged(s.Traits, self, upgrade, -1);
+			CheckCanManageConditions();
+			RevokeCondition(self, objectTokenShim[Pair.New(source, upgrade)]);
 		}
 
 		/// <summary>Returns true if the actor uses the given upgrade. Does not check the actual level of the upgrade.</summary>
 		public bool AcknowledgesUpgrade(Actor self, string upgrade)
 		{
-			CheckCanManageUpgrades();
-			return upgrades.ContainsKey(upgrade);
+			CheckCanManageConditions();
+			return state.ContainsKey(upgrade);
 		}
 
 		/// <summary>Returns true only if the actor can accept another level of the upgrade.</summary>
 		public bool AcceptsUpgrade(Actor self, string upgrade)
 		{
-			CheckCanManageUpgrades();
-
-			UpgradeState s;
-			if (!upgrades.TryGetValue(upgrade, out s))
+			CheckCanManageConditions();
+			bool enabled;
+			if (!conditionCache.TryGetValue(upgrade, out enabled))
 				return false;
 
-			return s.Traits.Any(up => up.AcceptsUpgradeLevel(self, upgrade, GetOverallLevel(up) + 1));
+			return !enabled;
 		}
 
 		public void RegisterWatcher(string upgrade, Action<int, int> action)
 		{
-			CheckCanManageUpgrades();
+			CheckCanManageConditions();
 
-			UpgradeState s;
-			if (!upgrades.TryGetValue(upgrade, out s))
+			ConditionState s;
+			if (!state.TryGetValue(upgrade, out s))
 				return;
 
 			s.Watchers.Add(action);
 		}
 
-		/// <summary>Watchers will be receiving notifications while the upgrade's level is nonzero.
-		/// They will also be provided with the number of ticks before the level returns to zero,
+		/// <summary>Watchers will be receiving notifications while the condition is enabled.
+		/// They will also be provided with the number of ticks before the condition is disabled,
 		/// as well as the duration in ticks of the timed upgrade (provided in the first call to
 		/// GrantTimedUpgrade).</summary>
-		public void Tick(Actor self)
+		void ITick.Tick(Actor self)
 		{
-			CheckCanManageUpgrades();
-
-			foreach (var u in timedUpgrades)
+			foreach (var u in timedConditions)
 			{
 				u.Tick();
 				foreach (var source in u.Sources)
 					if (source.Remaining <= 0)
-						RevokeUpgrade(self, u.Upgrade, u);
+						RevokeUpgrade(self, u.Condition, u);
 
 				u.Sources.RemoveWhere(source => source.Remaining <= 0);
 
-				foreach (var a in upgrades[u.Upgrade].Watchers)
+				foreach (var a in state[u.Condition].Watchers)
 					a(u.Duration, u.Remaining);
 			}
 
-			timedUpgrades.RemoveAll(u => u.Remaining <= 0);
+			timedConditions.RemoveAll(u => u.Remaining <= 0);
 		}
+
+		#endregion
 	}
 }
diff --git a/OpenRA.Mods.Common/Traits/Wanders.cs b/OpenRA.Mods.Common/Traits/Wanders.cs
index 02a963cc91..3c0f5983d5 100644
--- a/OpenRA.Mods.Common/Traits/Wanders.cs
+++ b/OpenRA.Mods.Common/Traits/Wanders.cs
@@ -31,7 +31,7 @@ namespace OpenRA.Mods.Common.Traits
 		public override object Create(ActorInitializer init) { return new Wanders(init.Self, this); }
 	}
 
-	public class Wanders : UpgradableTrait<WandersInfo>, INotifyCreated, INotifyIdle, INotifyBecomingIdle
+	public class Wanders : UpgradableTrait<WandersInfo>, INotifyIdle, INotifyBecomingIdle
 	{
 		readonly Actor self;
 		readonly WandersInfo info;
@@ -50,9 +50,11 @@ namespace OpenRA.Mods.Common.Traits
 			effectiveMoveRadius = info.WanderMoveRadius;
 		}
 
-		void INotifyCreated.Created(Actor self)
+		protected override void Created(Actor self)
 		{
 			move = self.Trait<IMove>() as IResolveOrder;
+
+			base.Created(self);
 		}
 
 		public virtual void OnBecomingIdle(Actor self)
diff --git a/OpenRA.Mods.Common/TraitsInterfaces.cs b/OpenRA.Mods.Common/TraitsInterfaces.cs
index 38044bd452..405ba38190 100644
--- a/OpenRA.Mods.Common/TraitsInterfaces.cs
+++ b/OpenRA.Mods.Common/TraitsInterfaces.cs
@@ -103,15 +103,14 @@ namespace OpenRA.Mods.Common.Traits
 	[RequireExplicitImplementation]
 	public interface INotifyPassengerExited { void OnPassengerExited(Actor self, Actor passenger); }
 
-	public interface IUpgradable
-	{
-		IEnumerable<string> UpgradeTypes { get; }
-		bool AcceptsUpgradeLevel(Actor self, string type, int level);
-		void UpgradeLevelChanged(Actor self, string type, int oldLevel, int newLevel);
-	}
+	[RequireExplicitImplementation]
+	public interface IConditionConsumerInfo : ITraitInfo { }
 
-	// Implement to construct before UpgradeManager
-	public interface IUpgradableInfo : ITraitInfo { }
+	public interface IConditionConsumer
+	{
+		IEnumerable<string> Conditions { get; }
+		void ConditionsChanged(Actor self, IReadOnlyDictionary<string, bool> conditions);
+	}
 
 	public interface INotifyHarvesterAction
 	{
diff --git a/OpenRA.Test/OpenRA.Game/BooleanExpressionTest.cs b/OpenRA.Test/OpenRA.Game/BooleanExpressionTest.cs
index 1b40536ff9..214778f623 100644
--- a/OpenRA.Test/OpenRA.Game/BooleanExpressionTest.cs
+++ b/OpenRA.Test/OpenRA.Game/BooleanExpressionTest.cs
@@ -21,11 +21,11 @@ namespace OpenRA.Test
 	[TestFixture]
 	public class BooleanExpressionTest
 	{
-		Dictionary<string, bool> testValues = new Dictionary<string, bool>()
+		IReadOnlyDictionary<string, bool> testValues = new ReadOnlyDictionary<string, bool>(new Dictionary<string, bool>()
 		{
 			{ "true", true },
 			{ "false", false }
-		};
+		});
 
 		void AssertFalse(string expression)
 		{