I like about one hour before sunrise. Mainly to let things settle down nicely and to hear the sounds of nature as the morning unfolds.
There's nothing like watching the woods come alive after sitting in the dark for a while! Alot of folks never experience that. Their missing out.
Lately, Ive been waiting to be able to see before making the final approach to my stand site. Over the years I have bumped alot deer walking in while its dark. Alot of that is on me for not having proper access. Some of it is just how it is on certain properties. (Ive also been packing in stand/sticks just about every hunt so that plays a roll. Alot of places i'll know the exact tree im going to, but set up still goes smoother with no need for a flash light)
Some properties i'll start trekking in when its still dark and im walking a creek or a bottom, but by the time i get to where im headed, i'll be able to see.
Im like a damn turtle. Id say about 15-20 steps and then stop, scan the area and make sure im clear before advancing. Takes a while to get where i am going.
I'll skirt deer occasionally, but rarely due i ever blow them out of an area. I hate the feeling of being blown at when its dark and your half way up the tree and not knowing what the hell just spooked