I had my first hand knit sock casualty this week.
I am not sure how well you can see the mishap, but it is at the back of the leg about halfway up. The only thing I can think of is that it was a weak spot in the yarn and after wearing them and washing them a number of times it just gave way. Because I really don’t know how else that particular spot would get worn out faster than the rest.
I considered repairing them, but I have so many skeins of sock yarn to knit up for new socks that I am okay with letting this pair go to the grave. What I might do is unravel both socks and reuse the yarn in my sock yarn blanket. What better way to let the socks live on.