I think you have to feel the pulse of the herd you're hunting. In my unique situation.....I have to get there extremely early.....or risk bumping deer. During the rut, last year, I went to stand at varying times. Sometimes I was in there 2 hours before first light (more a couple of times). Sometimes I waited 'til 9:00 and hunted the rest of the day.

Trial and error is how I came to this approach.