how many carbs and calories for maintenance?

I eat about 2000 calories and 50 carbs per day. My protein is usually well over 100g.

I am not a "tracker" per se.  I had surgery in Jun 08. I got to goal in about 10 mos so I have been maintaining for a while now. I have a good idea what "normal" is for me so I don't feel a need to track or keep that close an eye on what I eat or what the scale says. That having been said I am mindful of what I eat and what is going on with me emotionally.
I hike regularly but other than than don't exercise per se.
I don't really know how many calories I take in daily. I generally consume around 100 gms of protein and around the same amount of carbs with no re-gain so it seems to be working for me. Like Shel says everyone is different.

I am still tracking but my goal is to not have to track most of the time some day.

I eat about 2000-2500 calories a day, about 1700 net (i.e., after exercise). Carbs are around 150. Protein around 135.