I have been buying these socks for several years now, and have probably put hundreds of kms on a pair before a thin spot develops in wear points (big toe for me). I have narrow feet, so the extra support around the arch keeps them in place and they don't spiral around my foot like a lot of ankle socks do with daily wear (and no arch support). The thicker heel and ball of foot areas are perfect to give that little extra cushion in every step. The tops are a bit thinner for breatheability and they're moisture wicking, making them great as a summer sock!