I don't use DEET repellants at all. I have actually had much better luck with Mountain Martha's Z'off (all-natural, smell's like strong pine pitch) that I used to pick up at Fran Better's shop each year on my annual trek up there. Matter of fact, last night I exited my truck at my fishing spot and some gnats immediately swarmed around my head. I grabbed my hat (which had last been treated with a just 2 squirts of Z'off last Friday) and put it on and they disappeared. Best stuff I've ever used, bar none.
I also purchased another DEET-free repellant while on my Upper Connecticut River(NH) trip. It was called White Mountains Insect Repellent I believe, and came recommended by the guide. If a NH guide swears by it, with all the black flies and mosquitoes they deal with each year I figure it must work. My Z'off is finally running out so I'll begin using more of the other stuff now.
BTW, the way I learned it years ago, is that Skin So Soft is not actually an insect repellent but rather it makes the skin so oily, smoth that the mosquitoes apparently have a very hard time staying on your skin long enough to bite. But it doesn't actually act as a repellent.