I had all four done at once. A very light version of a general anaesthetic with loads of injections. Took an hour with a LOT of drilling but it was fine. ****ing painful about three hours later when the injections wore off but then the pills he gave me kicked in. Uncomfortable for a week (and you look a bit of a ****) but otherwise its no big deal.
Mine were deep but crooked. If yours are already coming out they literally just give it a tap and the whole thing takes ten minutes. If they are deeper its the full monty....