Is There An Ethical Statute of Limitations?

A couple of ethics questions today relating to time. In Confessions, Augustine puts his head in his hands lamenting the horrible crime he committed as a child -- sneaking into a neighbor's yard and stealing some pears. He wasn't hungry and had better pears in his tree. So why did he do it? Why? Is his character now forever scarred by it? The question is, when you screw up, is the result a mark on your moral permanent record or does the stain slowly fade out? Is there an amount of time after which you can no longer be held culpable for your earlier acts?

Consider two different versions of this question:

(1) Suppose you were busted. You did it and you got caught. Is there a period after which it becomes simply a fact of the world without the related condemnation of your character? Is it a function of whether there are still lingering ill effects of the act? If it was something for which responsibility was accepted and the situation was completely rectified, does that make a difference?

It may be an easier question when the act was a youthful indiscretion or done at a time when there were other causal factors, say, an addiction. In those case, you can always argue that "I'm now a different person," but what of the times you screw up as an adult?

(2) Even if there is a statute of limitations in the first case, does the clock start after you took responsibility or after the act? Suppose you did it and got away with it. All these years, no one noticed or no one figured out that it was you. Is there an amount of time after which if you cop to your actions that you no longer deserve condemnation? Or is it worse because you hid it? Is it a difference in degree or difference in kind if it is a serious or less serious screw up?