How to Treat Sheets So They Last
Wash in warm water using permanent press or casual cycle. The higher the temperature the rougher it is on the fabric.
Dry on permanent press or casual (not timed). These cycles sense when sheets are dry so you won’t expose them to unnecessary heat, which can cause shrinkage and damage.
Nix Wrinkles with the extended tumble option: it tumbles sheets intermittently (minus heat) so creases won’t form. Or toss in a damp washcloth for 10 minutes. It’s moisture will help smooth.
Source: Good Housekeeping