I've bought a total of 8 pair of these (in blue and black) and have gotten well over 500 days of heavy use of them. Only one sock has really worn out and another one or two show noticeable wear. The rest appear nearly new. Based on my experience, I'd estimate that (over the long haul) you'll need to buy only about 3 pair per year if you wear these every day!They're quite a bargain, especially if you search the site for the same Futuro socks direct from Amazon with FREE Super Saver Shipping!