Sized like handmade things are
Every listing states the exact size of that exact piece, because there is only one of it. Compare with something you already love wearing, not with a letter size.
Socks
Listed with an EU shoe size (for example EU 38). Hand-knit socks stretch: a size fits about one number up and down, so EU 38 suits most feet from 37 to 39. Wool relaxes with wear and springs back after washing.
Scarves & sets
Listed with real measurements, length by width (for example 2 m × 35 cm). Two metres wraps twice on most people and still hangs low. Set beanies follow the beanie rule below.
Beanies & mittens
Listed as head circumference, or one-size where the rib makes them truly stretchy. When in doubt, the listing says what head or hand it was knitted around.
Sweaters
Listed with pit-to-pit, length and sleeve, measured flat. Lay a sweater you love flat, measure it the same way, compare. Hand-knits do not follow S/M/L logic.
Between sizes, or nothing fits? That is what commissions are for: the same piece, knitted around your measurements, usually within two to three weeks.