I would "imagine" the answer to this question varies greatly and is dependent upon when the deer you're hunting are moving through the area you're hunting, that day.

Proximity to the type of area you're hunting would also play a big part (i.e. destination food source/funnel/transition area/proximity to bedding area).

I get to my stands when I do out of necessity......based on my experiences with varying my entrance times.

I've just never heard of a good reason NOT to get there early. Like I said....I nap REALLY well in my climber, anyways.