gm techniques – The road not taken, or should a GM allow replays?

Some people say adventures are supposed to be unique experiences that cannot be recreated. What if the player wants to replay the same thing from the beginning, but try a different fork in the road? Should GMs allow players to do that?

One thing that distinguishes tabletop gaming from computer gaming is its spontaneous nature. If you’re retreading old territory, it’s kind of taking away from that.

But if a GM is inclined to allow the replaying of an adventure, should the player be allowed to use the same character and keep all his previous XP and loot? Or perhaps allow the same character but start with nothing? Or perhaps only allow completely new characters?