I use permethrin on pants, gaiters and the bottom and straps of my hammock. If bugs keep walking across treated material, they die and fall off.

I dislike DEET - it will melt plastic. I use it on my hands (the backs) and then carefully wipe on each cheek, rather than spray it on my face - anything that makes my lips numb has to be Not Good For You. A headnet is a blessing in bug season - DEET is useful against mosquitos but does nothing for nuisance gnats and flies.