I'm adding an auto-enabled quest that checks against the player's previously installed version of The Revenge of Colette and removes deprecated spells if necessary. In case I need to use this quest again in the future, is there any way to make it run every time the person boots up the game?

You'd probably want stuff like that to happen on a per save basis. I'd go with http://www.creationkit.com/OnPlayerLoadGame_-_Actor.

If you need multiple checks, pass an actor from your mod as akActor and check different http://www.creationkit.com/Actorvalue for each needed GetGameLoaded check (or a different actor for that matter):

Event SomeEvent()	If GetGameLoaded(YourActor, "BrainCondition")		Debug.Trace("SomeEvent fired for the first time this save load.")	EndIfEndEventEvent SomeOtherEvent()	If GetGameLoaded(YourActor, "LeftMobilityCondition")		Debug.Trace("SomeOtherEvent fired for the first time this save load.")	EndIfEndEventBool Function GetGameLoaded(Actor akActor = None, String asActorValuehttp://forums.bethsoft.com/topic/1387601-repeatedly-auto-enable-quest/= "")	If akActor.GetActorValue(asActorValue)		akActor.SetActorValue(asActorValue, 0)		Return True	Else		Return False	EndIfEndFunction