I don't use a camera at all.. so my assistance in this matter is less than warranted.

However, to answer your last question.. what you would learn if you left your camera up all year is the very importance of "preferred food sources" and when and possibly how deer are using them. Once you do learn what a preferred food source is and where it is located you can start to find details behind certain animals.. and eventually may be able to correctly guess one deer's home range.. which in turn may lead to greater understanding of a specific animal's bedding habits throughout his/her home range and that relationship to a "preferred food source".

Whitetail need food.. water.. and cover to survive and will only travel as far as it needs to attain each. (except during the rut of course).

If one did use a trailcam all year on good food sources I believe much could be learned about an individual whitetail, his home range, and his bedding distances near a preferred food source. Provided the hunter had common sense.

That's just my opinion...