but see you had it in the body of your post. The fact is, if you're playing more than about 7 players, you're short-changing yourself (unless you have 10 HS All-Americans on your team). 78% of minutes to starters is less than 32 minutes per game per starter.
Knight is right too about sitting players in foul trouble. You used to never see coaches sit a player with 2 fouls in the first half. Now, that's the rule rather than the exception. The risk is that a player fouls out and has to sit. But if you sit him down earlier, it's like you're conceding the additional fouls that he might not commit. Obviously, you do need to sit a player who gets into deep foul trouble early (like 3 fouls in the first half or 4 fouls in the first 30 minutes), but coaches go way overboard on sitting players in foul trouble.