I'm going with about 50% on the dot.
Morning sits, usually. If not, I have a GPS mark, I just need to find a tree as close as possible to that. Around these parts, that's usually doable. Some areas you just have to pick a tree in advance. The area determines that, not me.
Evening sits, much more rarely. Usually some degree of scouting into an area.
I'm a big proponent of stage hunting if I have a buck checkmated. Start on the edges, work my way in for the kill. That strategy doesn't allow for a ton of advance planning.