I think both coach and player driven. If you are good, fit the scheme, fit the culture and consistently perform, have drive and have an upward trajectory, meet or exceed expectations, I am guessing you will be staying. If you do not check most or all of those boxes, on the fringe at all, you know it as a player and you should probably start looking.
Speed kills. But I am not only saying it in a running sense. Making the right decisions quickly and deliberately is just as important. And not quickly making difficult decisions quickly can be just as deadly to leaders, coaches and programs as a whole! New coaches, new approaches, new culture, and yes, some new players.