I usually use an arrow through the lungs. It stops them everytime. Seriously, I know the ethics police are going to have a picnic with this reply..... but if the deer is relaxed and walking along at a leasurely pace I just shoot if it's 25 and under. They're less likely to hear the bow go off or jump at the shot until it's too late. Just the slightest of leads and let it go. IF the shot is there I take it. If I have plenty of time for later shots I may wait, but I usually hunt some thick stuff and the holes are where they are. A deer at a little prance or one who has a little quickness to his step I may give a MMaaaaaaaaa to .... but more often I'll shoot a walking one or wait for him to stop on his own or let him go.