I took these socks as one of three pairs (the other two were NOT this sock) on a three month backpacking trip during which I walked about 15 miles every day. I hadn't worn them more than twice before I left, and washed and rotated them out every three days, but they developed holes after two weeks. They're admittedly thin, but for the price and Smartwool's reputation, I expected them to hold up for more than two weeks. I was disappointed to have to toss them so soon. That said, while they were worn, they were very comfortable, didn't slide around, and worked perfectly as a buffer between my foot and my flats. It seems these are best lightly used. They run true to size.