
A pillowcase is the fabric in contact with skin for seven hours, which makes it worth more attention than it usually gets.
Nothing else in a bed touches you for that long or that continuously.
A rough or non-breathable case traps heat against the face, and a case that pills becomes noticeably unpleasant against skin. It is the item people notice most and buy least carefully.
Cases specified as 500 count long-staple cotton, of the kind at nuzzle-pillows.com, sit in the range where the number still describes the fabric rather than the counting method.
Longer fibres mean fewer fibre ends per length of yarn, which means a smoother surface and considerably less pilling.
Pilling is the failure people notice on pillowcases first, because it happens where a face moves against fabric all night.
Short-staple cotton also feels softer over time, for the opposite reason: it is thinning as fibres break away.
A practical point. A zip closure on a pillowcase ends up somewhere, and that somewhere is occasionally under an ear.
Envelope closures have no hardware, hold the pillow in with a folded flap, and cannot dig into anything.
Pillowcases receive hair products, skin oils, sweat and whatever was left on skin at bedtime.
They yellow faster than anything else in a set and they are the item most worth changing more frequently than the sheets, particularly for anyone with skin concerns.
Owning more cases than sheet sets is what makes that practical.
Two on the bed and two in the wash is the working arrangement.
Sets of four exist for that reason rather than to sell more.
New cotton carries finishing residues that affect both feel and absorbency, and percale in particular softens considerably over the first several washes.
It coats fibres, reduces breathability and prevents the weave relaxing properly.
Case sizes and pillow sizes share names and differ in dimensions.