In basketball, when a starter gets into early foul trouble, the coach usually takes him out to save him for later. This is stupid for two reasons:
1. In theory, your team's performance at different points of the game is equally valuable. Why take out a starter early when he could be helping you build a lead? Why is it better to save him until later? Actually, taking a player out to save his minutes until the end of the game can make him less effective: if you are down and your opponent is managing the clock, you could get that player for fewer possessions. But in general, a player's performance in five minutes in the middle of the first half can be as valuable as his performance in the last five minutes: all baskets are worth the same amount at different points in the game.
2. If you take a player with foul trouble out, you are choosing to limit his playing time on the chance that he picks up more fouls. But he might not. Taking him out for foul trouble might mean you get him for fewer minutes than you would have if you just let him play. Don't take a starter with two or three fouls out and hope a substitute and the rest of the team plays well without him. Let him play as long as you know you have him; if he fouls out, then you put in a substitute and hope he and the rest of the team perform well.
I think basketball coaches should ignore foul trouble; they should play players when they know they have them available, not purposely limit the minutes to avoid the possibility of not having the player later. Possible objections to this zany strategy: the opponent may target the player to get him to draw more fouls, or the player could play more tentatively in order to avoid fouling. Any others?