Baby Appetite?

How long do your 3 month old babies nurse? My little guy has been nursing for only 5-12 minutes for what feels like weeks now. He used to nurse for 15-20 minutes the first month or two but has now drastically cut back nursing time.

I can tell he eats more efficiently and drains whatever boob he is nursing on decently, but never fully empties it before unlatching and either falling asleep or not relatching. Because of this he still nurses every 2 hours during the day. Is this still normal at 3 months?