How do you know when it’s time to make a change?

How do you decide when to make a (profound) change?
Is it when you’re dragged, kicking and screaming, toward an inevitable choice (i.e., no choice?)
Or the moment when something seems clearly right and you have the confidence to go with your gut?
Or, is it a more intellectual process of weighting choices and forecasting scenarios–and then deliberately choosing what seems best?
I’m making some decisions right now. One one level, my impulse is just to continue as is for as long as possible, hoping for the *right* choices to become clear. On the other hand, I need to make active choices–but not hasty ones.