my guess is that they do not move alot. even though it would make sense for them to change locations alot to avoid someone giving the US a tip as to where they are, there has to be alot of risk in moving OBL and AZ from place to place.
Agreed. UBL and Zawahiri are most likely only moving seasonally or when other specific events call for it.
Unlike Zarqawi in Iraq whom is moving quite frequently (though not every 6 hours or such like some speculate).