Darn Tough have at least 3X the lifespan of Smartwool in my experience. I bought three pairs of over-the-calf ultra-light ski socks
three years ago and have worn them for all my riding and snowboarding since. They still look brand new. I only paid $16 a pair for them, too. I used to go through two or three pairs of Smartwool a winter (holes at the balls and toes). I actually have family who work for Timberland (owners of Smartwool), but I still buy Darn Tough socks.
Shirts, on the other hand... I love my Smartwool shirts.