Don't know how they wear, because we just got them, but they're nice and thick.  They're also super soft and comfortable because they have a loopy inner knit (like terry cloth almost?) that cushions your foot. I was worried about the sizing as well, since they only had small and I couldn't figure out what that correlated to in kid shoe size. In case it helps someone else, these fits my 5-year-old son who has a little kid size 13 foot perfectly.