RE: What major factor convinces you to move your stand?
With that few deer in the area, if I knew I was in a good spot I would stay unless I saw deer using another trail. I think rather than move you should figure out why you are seeing no deer. Where are they? Are they only moving at night? Where is the food source? Water? Bedding? Has it moved since I scouted and put up my stand? How often am I hunting the stand? Am I doing something that is causing the deer to change patterns from when I scouted? Scent to much? Over hunting the stand? Sorry so long but if I know I am doing any of these mistakes or any of the deer factors have changed then it is time to move on and try some place else. I will have about 10 stands out in a number of different areas so it is easy to change spots for me but someplaces make it alot tougher.
If you are limited in the area you can hunt you might at least put up more than one stand so you can hunt the wind correctly. You also can switch stands and might notice something else you were missing. Deer change thier patterns so much during pre-rut and rut that sometimes pre-season scouting can give false information. Trail cam is another good way to tell deer movement. A $70 dollar trail cam on the trail to your stand may tell you when the deer are coming through. You might be too far up the trail and they get there after dark or something.
Sorry so long