Mending Heel Holes / Darning Socks

Dear Community,

Do you have any tips for mending holes in the heels of socks and darning socks? 

Is darning socks out of style, and do you just buy new ones instead?

I recently had to darn holes in my son’s favorite socks, which he is still attached to 13 years after his grandma’s death (while she was alive, she supplied us all with socks so we’d still have warm feet even when she was no longer with us).

Well, I managed the heel with a rather unattractive duplicate stitch. Since the hole was large, I stretched cross threads across it and then filled them in.

For the toe, I cut everything away, picked up the stitches from the last intact row, and then knitted a new toe.