RE: How often do you spray?
I go through a lot of the stuff. A good 3-4 of the big bottles easily every year. I don't know if it works or not, but I figure it can't hurt.
I will spray myself in each layer of clothes as I put them on. I spray my boots. I spray my bow, my pack, and my stand if I'm packing it in. I then get to my spot and once in a tree, give myself a once over again, focusing on my head, neck, hat, and hands. Every couple of hours on stand, I'll pull it back out when I'm bored and spray down again. If I do a full day sit, I'll likely spray myself 3-4 times through the day.
When I'm done hunting, anything that is a base layer, glove, hat, or facemask gets thrown in a seperate container and won't be worn again till it's washed. I'll wear an outside layer 2 times before washing. If I'm not outside, it's in a scent proof container including my boots, pack, etc. The bows stay outside the camp hanging in the open air.