Spend at least 15 minutes on a mattress in the store. By spending five minutes each on your back and both sides you will be more likely to determine if the mattress you are trying out is the right choice for you. If you sleep with a partner, try out mattresses together.
Among innerspring mattresses, construction quality and materials is more important than brand or model name.
You shouldn't overpay, but you shouldn't underpay either. You can find a quality mattress once you hit a minimum price point. Consumer Reports magazine says you should expect to pay about $1000 for a quality queen-size innerspring mattress set.
The mattress should support your body at every point. If you prefer, you can buy a mattress with extra support at the head, center or ends, or with "zoned" support, which offers different support levels for different parts of the body.
If you have difficulty rolling over, the bed is probably too soft. If the bed is too firm your hips and shoulders will feel uncomfortable. Lie on your back and try to slide your hand under the small of your back. If your hand slides too easily, the mattress may be too firm.
The gauge number, or thickness, of the springs determines the mattress's suspension. If you prefer firm suspension, look for a lower-gauge number (which means thicker spring wire); if you like soft suspension, go for a higher-gauge number (thinner spring wire). A good-quality full-size mattress has a gauge of between 12.75 (more firm) and 15 (less firm).
Besides wire gauge, the number of coils also determines a mattress's support. Manufacturers tout different configurations and number of coils as providing the best support, but most experts say that, after a certain number of coils, it doesn't make a big difference. A good-quality full-size mattress should have at least 300 coils (although many premium models have close to 400), a queen-size mattress should have a minimum of 375 and a king-size mattress should have no less than 450.
A firm mattress has fewer layers and stiffer materials, while a softer mattress has extra layers or pillow-top cushioning. Less expensive mattresses may have vinyl ticking (the outermost layer of the mattress) instead of polyester or a cotton-polyester blend, but all should hold up over time. As for top padding, soft foam is preferable to polyester batting, which tends to lose loft. Convoluted foam in the middle padding (which looks like an egg carton) should feel softer and more comfortable than straight foam.
Some higher-end mattresses have fancy designs sewn into the fabric (rather than printed on), but the use of silk in the design is really just a marketing ploy. Stitch designs, however, should be uniform and unbroken to prevent the fabric from loosening.
You should buy a mattress and box spring as a set. The two parts are engineered to work together; using an old box spring will reduce a mattress's comfort and longevity. Many manufacturers will void their warranty if you do not purchase a matching set. Also, you should always use a bed frame, and make sure there is center support for larger-sized mattress sets.
If you have allergies, look for nonallergenic or antimicrobial materials in the padding.
If you plan on co-sleeping with an infant, pillow-top mattresses and waterbeds can be a safety hazard and are not recommended.
New mattresses are thicker now, so your old sheets may no longer fit. Widths have gone from about seven inches to more than nine inches, so you may need sheets with a deep-pocket corner.
Ask about disposal of your old mattress. Some stores offer free disposal, while some only carry it to the curb.
Look for a fire-resistant mattress. A new mattress flammability standard has been in effect since July 2007. Stores are being allowed to still sell mattresses that don't comply with the standard until they are gone, however. Mattresses meeting the standard have a non-removable label, so be sure to look for it when you buy.
Ventilate a new mattress for a few hours. Open the windows in the room and leave the bed unmade.