I LOVE my Darn Tough running socks. I cannot tell new from old by feel or comfort. I cant even guess how many miles are on my oldest pair, more than a thousand for sure.
I think I use the No-show ultra-lite, but they have a new running line of socks now so I might check some of those out for fun. Not that I need any. I have 4 pair of Darn Tough and that is more than enough to keep in rotation for me.
Oh, and their socks have a well-regarded Lifetime guarantee. I have never needed to take them up on it but I have heard they will stand behind their socks no matter what. I think there is a legend that they once replaced a sock that went through a dog’s digestive tract.