When ARC Consulting surveyed 400 adults for the Better Sleep Council, they found that 8 in 10 thought a bad mattress could cause sleep problems. Ironically, nearly half said they had a "bad" or "very bad" mattress they were trying to sleep on.

You need a new mattress if:

Yours is 10 years or older

The topography of your mattress resembles a mountain range, with all its peaks, valleys, and slopes

You wake up feeling sore or stiff, despite not being physically active the day before

Although no one mattress works best for everbody, there are some guidelines to follow. Make sure you buy one that's larger than you think you will need, especially if you sleep with someone else. Other key considerations:

Firmness. This is strictly an individual decision. But make sure you try out any mattress in the store. Lie on it. Roll over. Get into your typical sleeping position. Consumer Reports found that firmer mattresses don't resist permanent body sagging any better than softer mattresses; that thicker mattresses sag more than thinner ones; and that the more padding there is, the greater the possibility the mattress will sag.

Frame. Make sure you get a sturdy, quality frame, one with at least 10 slats and a fifth leg as a center support.

Maintenance. Make sure you turn your mattress over and upside down at least every three months.