Focus on fiber. Traditional cotton remains your best choice for sheets that combine easy care, comfort, and durability. If you're a stickler for sheets that look their best and you don't want to iron, look for cotton-polyester blends.

Note fit and construction. For the new, thicker mattresses, we found that buying bigger is best. If your mattress is 18 inches thick, choose sheets that claim 20 inches, to avoid pop-off corners.

Look for elastic all around the edges of a fitted sheet. Elastic along each side of the sheet is second best. Elastic in the corners only is the last choice. Check the seams on the wide hem of the top sheet and on the pillowcases. Stitches should be tidy, tight, and fairly small.

Never mind thread count. Thread counts between 200 and 400 are fine. Within that range, a higher number may provide a softer feel. With counts over 400, the main difference is price.

Guard against poor quality. In the store, make sure all pieces of the set are there and in good condition. With darker fabrics, buy and set aside extra pillowcases that can document color changes in laundering over time. That's especially important if you're buying coordinating bedding or accessories. Keep receipts and ask for your money back if the sheets fade after laundering or do not otherwise hold up.