I spray my vest and waders with Permanone (Premethrin) which causes ticks to fall off. If they stay on the clothing, they die.
On my skin I use Cutter Advanced mosquito repellant which uses Picaridin instead of DEET. It which does not destroy fly line.
Appalachian Mountain Club's Equipped: Picaridin vs. DEET: Face-off of the buzzer beaters