I sit in my stand until I see deer approach and then I will ease into the standing position for the shot. I will also stand every once in a while to break from the sitting position. I have less movement when sitting.
I sit 98% of the time and have taken 98% of my animals sitting.... I stand to stretch every now and then when there are no deer around. I know a lot of the guys on here use climbing stands, I use a climber about 1% of the time I hunt, the rest of the time I spend in a tripod, double bull or a hang on with 360deg rotation.... So I can remain seated and still get all possible shot opportunities....
I try to set up my stands so that I can shoot in a seated position in the direction of anticipated deer movement. That said, I have never shot a deer in a seated position. I will usually stand at the "prime" times like alot of the guys said though.
Having worked in a bank where I had to stand for 8.5 hours... wearing nylons and heels... Standing for 4 or 5 hours straight in a treestand is a piece of cake. I do sometimes sit for spell when I get out at 2pm and I know the earliest the deer are going to move is 5pm. 98% of my hunting is standing.
I stand about 90 percent of the time. I will sit to relax but in my Summit Goliath shooting in a sitting position isn't possible with my bow.