Anymore battery life on the new trail cameras is great, so I no longer really worry about settings for a long battery life.
As far as settings it depends on where it is set. If setting on a trail situation where deer are just moving thru, I will set for the shortest delay and will usually set for 3 picture burst. It is surprising how many other deer you get on the 3rd picture. If setting on bait then I will usually set it for 1 pic every minute.