Ah, the trick here is to buy all your socks at the same time, and open all the packs at once. Don't just open a pack every now and then, or they'll age differently and you get the variation in wear and tear. Then once you're down to a few days' worth of raggedy socks, throw them all out at once and open the next batch.
(Source: Am a fellow black-sock-only person who made the above mistake last time around.)
(Source: Am a fellow black-sock-only person who made the above mistake last time around.)