I tend to not re-watch things, mainly because I get no enjoyment out of something if I already know what's going to happen. However if I go a few years without watching a show, I'll restart the season I left off in, or the series entirely if I wasn't that far in. That said, I do however watch The Big Bang Theory and NCIS when they're on. And I would probably willingly re-watch Doctor Who, but that's probably it.