As is usually the case, it depends on the circumstances. I have hunted places where there was only one suitable tree for the local turkeys to roost in...and they all roosted there. Generally speaking, however, if there are a number of suitable trees in a location, my experience is that the turkeys will roost in several trees rather than a single one.
Most of the places I have hunted, the turkeys have been pretty loyal to roosting in the same group of trees...or at least the same general area...night after night. With enough disturbance, though, they will often relocate and roost elsewhere if other roosting habitat is available.
It also seems to me that, of the subspecies, Rio Grandes and Merriam's have a tendency to be more loyal to roosting in the same places than the others...at least that has been my observation in the places I have hunted.