The land I have to hunt is in what we call the hill country and when you get in the fingers that I hunt SWIRLING is a big issue. I too would not be able to hunt if wind direction was the only factor to take into consideration as it changes constantly in thses fingers. Don't get me wrong there is usually a prodominate wind direction but once it hits the hills it starts swirling in the worst kind of way, The area I hunt is on the northwest side of a hill that runs southwest to northeast, once the wind(prodominately out of the southwest during bowseason)tops the hill it starts going crazy through the fingers I hunt. I still hunt the wind but I also check it while on stand, I also have the same problem with deer coming from any direction even though I try to put myself in a situation that they would have a hard time coming from behind me.
I wash my cloths in scent free soap and I use scent killer sprays.....I admit it I am a user!!!!!
If it can help me even in the least, I use it and it seems to work better than nothing at all when the wind is not predictable....