I'm trying to find the right balance in big games for letting the subs come in to give the starters a breather. In one such big game today, I had a lead in the final 2 minutes, but gave up a 50 yard pass play that ended up costing me the game. On that play, my two weakest DB's were in the game as safeties. Should I have let the starters stay in the game even though they would have been below 90 or 85 fatigue level? I'm still confused about how much difference fatigue levels make.