A compression sock works because of its elastic fibres. Those fibres are also the part that wears out first, and how you wash the sock has more influence on that than how often you wear it. The routine below is simple and takes very little time.
Wash them after every wear
Skin oils, sweat and dust settle into the knit during the day and gradually break down elastane. Washing after each wear is not about hygiene alone — it is what keeps the stretch alive. If you wear compression socks daily, two or three pairs in rotation means you always have a clean, fully recovered pair ready.
Cool water, gentle detergent
Wash at 30 °C or cooler. Heat is what relaxes elastic fibres permanently, and once a sock has lost its recovery it will not come back. Use a mild liquid detergent. Skip fabric softener: it coats the fibres and leaves them slack. Skip bleach and stain removers too.
By hand or on a delicate cycle
Hand washing is gentlest. Fill a basin with cool water and a little detergent, submerge the socks, knead them for a minute, then rinse until the water runs clear. In the machine, use a delicate or wool cycle at low spin and put the socks in a mesh laundry bag so they are not stretched around the drum or snagged by zips and hooks.
Never wring them out
Twisting forces the knit out of shape along the twist line. Instead press the sock between your palms, or roll it in a towel and press down, to push the water out.
Air dry, away from heat
Lay the socks flat or hang them over a rack and let them dry at room temperature. Keep them out of the tumble dryer and off radiators and sunny windowsills — the same heat rule as washing. Drying usually takes a few hours.
When to replace a pair
Elastic fibres wear out with use, so compression socks are a consumable. Signs a pair is past its best: the top band no longer stays up, the sock feels loose the moment you put it on, or the knit looks thin and slack around the ankle and heel. Replace them when the fit stops feeling firm — a stretched-out sock is simply a sock.
Storing them
Fold the pair flat rather than rolling one sock into the other, which stretches the cuff over time. Keep them in a drawer away from direct sunlight.