In college basketball, there are essentially four main objectives of calling a timeout:
1. To keep possession of the ball.
2. To provide players rest or recovery from injury.
3. To stop the opponent’s momentum.
4. To draw up a play.
UNC coach Roy Williams has a fairly well-deserved reputation for being peculiar with his timeout usage and lack thereof. The first two functions above are ones likely every coach uses from time to time, though it does seem like Heels players are discouraged from calling a timeout to escape pressure until at least the very end of the game.