It hard to give you a straight answer because it really depends on your opponent, the stamina of your players and whether you have quality backups so you will have to judge on a week by week basis as there is no perfect formula.
Opponent: If your squad is unable to beat your opponent convincingly, your coach will tend to give your starters more minutes to try and win the game or at least to stay ahead. If you manage to blowout your opponent, your starters will play less minutes and get benched in the 4th quarter
Stamina: The higher the stamina of your starters, the longer they tend to stay on the court without needing to be replaced.
Quality of backups: The better the backups, the less minutes your starters will play as the coach can afford to give the starters more rest without a huge drop in skill