There’s nothing warmer than a hand-knit wool sock, but a pair can take anywhere from 10 to 40 hours to knit. A trick I use for old, worn-out pairs saves a lot of time and half the yarn.
When the foot has been repaired so many times that there’s nothing left to darn into, knit a new foot, minus the cuff of the pattern. Then cut off the old foot, hem the base of the cuff so that it doesn’t unravel and sew the new footie to the old cuff. I’ve done this many times and have even used the cuffs from machine-knit socks of the same weight yarn.