If I play long stretches, I usually binge play, then stop once I feel like I'm hitting a wall. However, if I'm playing a tourney and I bust, I like to give myself at least a 15-20 minute break before I decide to continue with more of them. I know I probably don't give myself enough rest time, but when I'm in the zone it's hard to stop. Unfortunately with tourneys I find I suffer burn out a lot quicker and I find it a lot harder to concentrate, than if I were playing cash games. I'm beginning to think for that reason, I probably should be playing more cash to take advantage of the flexibility they provide.