I guess I’m still old school and darn my socks. What I have found that works the quickest & easiest way for me is to use a curved needle or regular needle with a large eye, embroidery thread, and a light bulb. Put the light bulb into the sock down to the toe area and make a couple of stitches with the embroidery thread and you’re done. The light bulb gives you something to hold & secure the area you wish to darn, the embroidery thread is thick, so it doesn’t take but a couple of stitches to close the hole & using a curved needle makes it easier (for me) to quickly make a couple of passes thru the hole to close it (of course that depends on the size of the hole! LOL!).
I use a light bulb (not the spiral fluorescent bulbs but a regular rounded one) because they are always handy. I do have a wooden darning egg, but it is in my large sewing notion box & I don’t always want to drag it out. I use the embroidery thread because it is several threads thick and will hold a stitch better in socks so I don’t have to go back AGAIN later to redo it.
When I’m browsing Thrift Stores or Yard sales I keep an eye out for old sewing boxes, and notions and can pick up embroidery thread & other sewing needs for pennies. The embroidery thread doesn’t break nearly as easily as regular thread (even if it is doubled). In a pinch, I have also used twine that is always in my “junk drawer”.
I also keep a small mesh laundry bag in the bathroom to put socks in that need darning. The last few years I have kept a ziplock baggie with needles, threads of different colors, a needle threader (for my old eyes that can’t see the eye of the needle to thread), a small pair of scissors (to cut the thread) & a light bulb. Saves lots of time by having everything right there. How many times do you put off darning socks because you don’t want to have to dig out your sewing notions?? Keep the baggie in with the socks that need darning. I know where the socks are that need repairing and before I do laundry, I will grab that laundry bag, darn the socks and they are now ready to wash. If you don’t keep them separate from all your dirty socks, you will spend extra time to look at each sock trying to find the one with holes. I get my small mesh laundry bags at Dollar Tree. The reason I keep it in the bathroom is that is where I’m usually removing clothes/socks, etc., to take a shower.
I also have a mesh laundry bag where I put my socks that don’t have matches. If after several weeks of doing laundry (and cleaning the house) & I don’t find the missing sock, I will use those socks to put over my hand for quick dusting jobs. I really like white cotton socks or men’s tube socks when I need to do a heavy cleaning project like wiping down the inside of the fridge. Spray the fridge with a vinegar/water solution & wipe it down. I have many uses for old mismatched socks.