I start looking for opportunities at UTG+2. I don't actually leave at the end of the hand though. I look at my cards and if I don't want to play them I just leave them slightly closer to the dealer and walk away (basically mucking out of turn). If I decide to play that hand, then I'll try next to hand, and then the hand after that. If I somehow wind up with 3 great
hands in a row I would wait another round to leave, but I haven't been that lucky yet. By leaving at the start of the hand instead of the end, that adds enough time that I will usually miss one less hand. And I would rather miss hands out of position anyways.