I used permethrin in past, works well. I heard it lasts multiple washes, but never wash clothes during season, just before season. Then had a few ticks (probably seed ticks) on me in Dec, 20 degrees out, hunting on ground. Found out permethrin should be applied every 6 weeks. Saw online they are attracted to our CO2, so figures got some while on the ground. Ever deer or hog I shot had tons on their belly or in hide. Weird how they hide once you start field dressing...I won't see them again until I start skinning, never had one leave animal to attach on me. I avoid touching fur during skinning.