Obviously how long you leave your cameras out depends a lot on how much time you can affored to spend moving/checking them but there are several reasons why I feel they should be out year round for deer:
1) Find survivors after the hunting season. Sometimes the big boys won't show their face again til january/february after being pressured all season.
2) By May a mature buck will already be identifiable. If you start your search for mature bucks in May, you can check a lot of different areas by moving your cameras around every 2 weeks. I like to use mineral licks or supplemental feeding during the summer when they're in bachelor groups. There's a good chance those mature bucks you found in May will still be there in october/november.
Here is a buck in mid-may, and the same buck in november. Yearlings will only have about an inch of growth in mid may.