i have rewatched the original star wars trilogy and then the prequels with my kids when they were old enough. mostly to make sure that they would see the original trilogy first before watching anything else star wars related as that might spoil some of the surprise moments for them.

generally i only rewatch something if i want to share it with my family or friends. did that with avatar, and will probably do it with lord of the rings, star trek and some other classics. ghostbusters for example. since a new one just came out recently, i am not letting my kids watch that until they have at least seen the original.