The deep pocket question: will it stay on the corners

The most common complaint about any fitted cover, ours or anyone else's, is some version of the corner came off at 3 a.m. Nearly every time, the cover was fine and the measurement was skipped.

Measure the mattress, not the bed

Run a tape from the top surface of the mattress down to its bottom edge. Do not include the boxspring or the frame. If a topper lives on the bed permanently, add its height too, the skirt has to travel over both.

What the numbers mean

• Up to 12 inches: almost any fitted skirt holds, including older ones.
• 12 to 16 inches: standard territory for our deep pocket skirts.
• 16 to 20 inches: the top of the stretch range. It fits, but put the corners on last and pull the skirt well under the mattress.

Why corners pop anyway

Three usual reasons. The skirt is shallow for the stack, often because a topper joined the bed after the protector was bought. The elastic has been through too many hot dryer cycles and lost its snap. Or the cover is riding on a slick knit mattress top with nothing to grip, in which case tucking the skirt deeper under the mattress does more than buying anything new.

A cover that fits does its work silently. If you are wrestling a corner more than once a week, remeasure the stack, the answer is usually in the tape.