What district are you in? Usually store managers stay around 5 years from my experience here. Ours has been here about 9. The stores closer to the city centers seem to be rotated more often though.
Store managers can stay the rest of their life in one store if they do a good job and like the store. Bad store managers get demoted to co manager eventually, after wrecking 2 or 3 stores.
store managers don't have to move around like the co managers. they are sometimes offered a bigger store for more $$ but thats it.
That doesn't seem to be the case at my store. FOUR store managers in about 4 years. Most of those who were moved, were moved (supposedly) because they were good, and needed to help other less-successful stores.