I've worn these under ski pants for back country adventures, under my dry suit on 20 degree river paddles, and in my sleeping bag and around camp. After all of the beatings, soakings, stretching, and washings they don't look or work any different than they did out of the package. Picked up a second pair because I thought as much as I use them they wouldn't last and the second pair is still sitting in the packaging in the drawer. There has been minimal to no piling and not a stitch has moved. They are thick enough to be warm but thin enough to fit under most other garments even with lightweight tights on. I do miss having "front access" but not enough to wear something else. Highly recommended.