My MIL has two pairs of socks I knit her at the start of this decade. I'm working on another pair, because it's high time she got some more... and in checking the others to confirm my length is good I realized just how high time it was: one hole, 7 bare spots across the two pair. I still need to darn the other pair, but the pair with a full on hole is all tidy now:
Each spot repaired/reinforced takes about 45 minutes of TV, give or take. Well worth the time: mending is a holy activity