I just went on a 2 hour hike and was seriously annoyed by many insects that tried to get a bite of me. Through years of experimentation on hikes, I have so far arrived at using a 75% DEET solution that I liberally deposit over myself.
While very effective after application, I find that the effect only lasts around 15 minutes - presumably due to me sweating a lot, which might have a converse effect to the repellent (just speculating, really). On today's hike, I went through 50 ml of repellent, since I had to keep reapplying it often.
Is there a particular type of insect repellent that is effective in such situations? DEET has so far been the only thing I actually notice driving the insects away but I wonder if there are some more "sticky" formulations of it that might work (what I am using right now appears to just be a basic liquid solution without much additive effects). How do you cope with insects in such a case?