A pair of socks, you recognize at the top. If you hold the top of the two socks together, and they are as much stretched, they belong together. Is one sock less stretched, then it is clearly not a couple.
My husband and three sons have about the same shoe size and the same type of socks (plain black, brown, dark blue). It was completely crazy to search together constantly all the socks in pairs in the clean laundry. Only those of the youngest were recognizable turned inside dumplings which I also did extra work with good turn. I was fed up of all the work that mountain socks and the guys hated because they often lost their socks. Had they just bought new and they ended up with a brother. There I found the following: I bought four bags lingerie and their initials embroidered. They save their own dirty socks in the bag, and when I go run a wash they deliver them. The dense bag goes into washer and dryer and then get back. Everyone happy, they have guaranteed their own socks and I need nothing more to look at each other, they do. Moreover, the youngest now may well turn on its own dumplings!