Create, delete, create event handlers


At the moment I create an onEnterFrame function to ease a movie clip into view. I then delete it. I want to be able to recreate a similar onEnterFrame function later to swoosh the movie clip out of view. At the moment weird things happen when I try and do the second onEnterFrame. Am I doing something illegal here?
I know I could put this all in the original onEnterFrame, but I don’t wanna be wasting processor time doing an if statement every frame to work out if it’s time to swoosh out the movieclip. Or should I not worry because that’s negligible cpu time?