When I was in my 20s I went back. We broke up primarily because we didn't spend enough time together and I got tired of waiting. I may have done that twice but I don't remember the other guy. In my late 20s I realized if we broke up for a valid reason things probably wouldn't be any different the second time around. What bothered me then still bothers me.
I would only consider it at this point if we split for something that wasn't about character or the way we related; i.e. one of us relocated because of a job, something like that