I don't think I'd do that unless they wore out faster than expected. If socks last you lifetime, you aren't wearing them. You certainly aren't wearing them working. That seems abusive of their good will. I have some pretty old socks, but I've repaired them numerous times. Also, irregulars(what Marshalls has) aren't covered. This is from their FAQ(emphasis mine)...
Our socks are guaranteed to be the most comfortable, durable, and best fitting socks you can buy. In a nutshell, if you wear a hole in them, we will replace them free of charge, for life. Things that generally are not covered—disappeared in the dryer, the dog ate them, too close to a campfire, theft by friend or foe, etc., etc.
However, all claims made in good faith will be considered.
Please note, socks purchased as seconds or irregulars are not covered by our warranty. For more information about our Unconditional Lifetime Guarantee or to start a warranty claim, visit
Our Guarantee page.
Nobody in good faith can expect socks to last forever. It's like people that returned Craftsman powertapes for exchange; C'mon... Powertapes are a consumable resource. If it doesn't break, you aren't using it. The companies believe in their product enough to give a very nice warranty(rare these days). Overusing it will cause that warranty to go away, and it becomes a hassle even getting defects taken care of. If I judge I got value from an item, I call it good, and buy another one.