Seems like I've been wearing this model of Thorlo's for twenty years. I buy about six pairs at a time and rotate through them for 4 to 6 years until they're too worn to wear and then buy more and do the same. Same high quality, same great wear and same comfortable sock day after day and year after year. I just bought six new pair and socks are one thing I know I won't have to worry about for a very long time. Buy'em!