Whether you are hand washing or machine washing, use cold water or lukewarm water (at the warmest) to wash socks. That will help keep colors from running and will avoid putting unnecessary stress on the fibers. High heat will cause damage, whether that’s in the washing or the drying stage. You can skip it.
This means you have two washing options, generally. The first is to hand wash them. The second is to send your knit socks through the washing machine in a mesh bag and use the gentle cycle. I generally avoid washing socks in the machine if I can, though. Agitation, soap, and water is the way to felt wool, and if you add heat to the mix, you’ve got a recipe for ruined socks on your hands. For me, it’s just not worth the risk.
Keeping your socks out of the dryer is super important if you want to avoid felting them. When you’re done washing your socks, remove excess water, so they dry quickly, by rolling them up in a dry towel and stepping on it, or by sending them through the washing machine on the spin cycle only. I’ve become a fan of line drying my socks on a bamboo drying rack. You can also just lay them flat to dry.
Frequent washing causes more wear of your socks. If you wash them every time you wear them, they’ll start showing signs of wear that much sooner. Wool is naturally an odor-resistant material. If the socks are not dirty or smelly, you can set them aside and wear them a few times before washing them.
The truth is that there is no point in having all of these beautiful handknits that you never use. Either you wear holes in them or the moths will, so you might as well get some enjoyment out of the whole making process. Being too precious about your knit socks will mean you don’t get to spend as much time with them.