20 in game days they are set to respawn. If you revisit a previously cleared dungeon the enemies are set to the scaled level they were at when you entered. Example a cave you went into at level 1 won't contain the higher levelled bandit types upon entering a second time at level 20.
Ah, I see now.
u are reading too much into this game bro, it isn't that deep. Just buy Kingdoms of Amalur in a a couple of weeks. Now that game is going to be awesome.
How so? Kingdoms of Amalur does look good, but this is not the time or place to bring that up... I was looking to do something when I'm not questing, in order to gain more money for a trophy and to decorate housing across Skyrim.