One of the young gear testers I do a trip with once in awhile, suggested over a year ago to give Ice Breaker wool shirts a try. She says she can go days without a shirt getting smelly. I've used a couple pieces so far and it seems great for winter use, I'll have to give it a try in warmer seasons. I've used the 150 weight so far and have a few heavier pieces that I just can't bring myself to use much, you know, its new and un-used, expensive don't wanna get it dirty thing. I have other shirts that have lots of trips left in them, so I'm reluctant to cast them aside and the closet space is getting full of clothes anyway.