Getting started

You should think about buying a new mattress if you wake up tired or achy, you tend to sleep better at hotels than at home, your mattress looks saggy or lumpy, you're over 40, or your mattress is at least five to seven years old. Use this mattress guide to help with your purchase.

Choose a size

Most sleepers shift positions during the night, and cramped quarters can keep them from moving freely. Standard mattress dimensions are king, 76x80 inches; California king, 72x84 inches; queen, 60x80 inches; full, or double, 53x75 inches; and twin, 38x75 inches.

Consider an innerspring

A conventional innerspring mattress is the most common choice and often the least expensive. Memory foam, which was developed to protect astronauts against g-forces, is heat-sensitive and conforms to your body. Not all memory foam feels the same, and it can take time to get used to. Many of today's innersprings, billed "hybrids," add a layer of foam over the springs. Another option is an adjustable-air mattress; with this inflatable kind, you can choose a different firmness for each half of the bed. Select Comfort (which manufactures Sleep Number) is the major brand, though other manufacturers have entered the fray.