I agree that darn tough lives up to their hype. I was gifted a pair of smartwool socks a year ago and was disappointed with the feel and comfort compared to darn tough, especially when they're almost the same price. I figure, if you're going to spend a ridiculous amount on socks, you may as well get the best.
I've also returned a pair with no issues, one sock developed a hole after around 3 years. Super easy and quick, they processed it in only a week. Just an FYI, they don't send you a new copy of the same socks back. Rather, they give you store credit to buy a new pair on their website. Good if you want to buy a different pair than before, bad because shipping isn't free unless you buy 2 pairs.
The darn toughs are probably the most frugal option if you consistently utilize the warranty.