Smartwool was my first none synthetic baselaye and I loved it from the first time I put it on. It was extremely warm, breathable, and comfortable. I wore it tons. However, after some use, the bottom of it pills...not a little...ALOT. I washed and hung dry it, and the pilling still happened. I asked our Smartwool rep and he said it was because it was rubbing on my pants and it was causing the pilling. Bottom line, to stop the pilling, tuck it in.