I haven't got a clue how to darn or sew. (I hate anything to do with sewing and I haven't got the patience to even thread a needle!) I buy new ones, they are fairly cheap so no problem. The old ones can be chucked out or used for cleaning rags (if they are clean of course)
Definately discard....lifes too short for darning.
Would you really want to spend it darning socks? lol
Neither. I wash them one last time and then they join my 'holiday' pile, to be taken on the next long-haul holiday and left in some far-flung part of the globe in a clothes bank. I've done this for several years now - it saves on washing hen you get home, and the space that the old clothes vacate in the suitcase can be re-used on the return trip for gifts and/or new clothing items
nope i stretch it, tie a knot in it and toss to dogs to play with
Buy new socks.