After several years I wore a hole in a pair of Darn Tough socks. My feet get cold when I sleep, even in the summer, so I wear my socks from shower to shower and I don't wear slippers in the house. It's amazing to me that these socks last as long as they do, and Darn Tough guarantees them for life. I dropped the socks off at the post office 11 days ago and my new replacements arrived today-free. They're as good backing their product as Leupold or RCBS.