It depends on where you live I suppose. Though here where the deer move off their fall range to winter(yard up), the best time for me is prior to spring fully hatching. The leaves are down, the snow is melting and everything is basically as it was during the previous fall (ie:trails, rubs, etc.). I scout year round but this is the best time to get a handle on general movements in a indepth manner without distrubing the area to much.
If I had to pick my next favorite time to be scouting, it is while hunting. I look at this way you have to be in the woods anyway might as well use the time to be more effective. I scout a lot more then I hunt.
