The short version
Darn Tough is the r/BuyItForLife sock, and the honest reason isn't that the knit is magic. It's the warranty. Darn Tough will replace any sock, for any reason, for as long as you own it. No receipt. You mail them the dead sock or bring it to a dealer, they send a new one. A $25 sock you never buy again is cheaper than $8 socks you replace yearly.
The socks themselves are good. Dense merino-nylon knit, a snug fit that doesn't slide down, and they're made in Vermont. Most owners report several years before the first hole. Some report much less, which is where the warranty comes in.
The complaint about the winner
A vocal minority on r/BuyItForLife says Darn Tough's durability has slipped: "They're okay socks, it's the warranty that makes them good." Others find the fit too snug in the toe box. And $25 a pair is genuinely a lot to hand over the first time. The warranty makes the math work, but only if you actually mail the socks back, which many people never do.
If $25 a pair is too much
People Socks sells 4-packs of 71% merino crew socks, made in the USA, for around $35. That's about $9 a pair. They come up in nearly every "alternative to Darn Tough" thread, they're thicker than most cheap merino, and owners report two to four years of use. There's no warranty. At $9 you won't miss it.
Costco's Kirkland Signature merino socks are the other budget answer, and one r/BuyItForLife test even ranked them a point above Darn Tough. They're around $15 for four pairs in-store, but they're in-store only and seasonal; online resellers charge triple.
Why not the others
- Smartwool (around $22 to $25): plusher and warmer than Darn Tough and some people prefer them. Also a lifetime warranty. They wear through faster at the heel, which is why Darn Tough wins the durability argument.
- Bombas (around $15 to $18): comfortable, heavily marketed, and the recurring r/BuyItForLife disappointment. Multiple threads titled some version of "Bombas socks have let me down," with holes inside a year. Their warranty exists but is less generous.
- Wigwam, Fox River, Farm to Feet (around $15 to $20): all decent, all USA-made, none with Darn Tough's warranty or reputation.
- Cotton anything: cotton holds sweat, bunches, and wears through fast. This is why you're reading a page about socks.
Which one for you
You're done buying socks forever and will actually use the warranty: Darn Tough. You want good merino socks for under $10 a pair: People Socks. You live near a Costco: check the Kirkland bin first.