I've become pretty convinced deer flies like VG. I've taken to using repellent for the first time in my life. I'm not allergic to mosquitoes (they bite me but I don't get any welts or itchiness from them... I'm among the lucky few) and for whatever reason, chiggers and noseeums just leave me alone. So, I've never used repellent... Until I started vaping and the deer flies decided I must taste good. Now, nothing short of Sawyer 100% Deet or 20% Picardin keeps them off me. And, I do mean that. The regular box store rattle cans of "off" or "cutter" or whatever just aren't up to the task. 100% deet when I'm not using or wearing anything synthetic, and 20% picardin for when I have to touch any nylon or plastic gear. The Deet lasts longer between applications, but it eats plastic. The picardin is supposedly better for ticks and such, but has to be reapplied more often.