Mattresses -- even high quality mattresses -- generally have a life span of about five to seven years, according to the Better Sleep Council. How long your particular mattress lasts depends on a number of factors, including the manufacturer, how much it has been used and whether it has been cared for properly and rotated regularly. In general, though, you should expect to replace your mattress at least every seven years, or sooner if you are experiencing discomfort or if the mattress is damaged.
Over time human bodies change, and fluctuations in weight, as well as the stresses of aging, can cause your mattress to feel uncomfortable, even if it is still structurally adequate. If you find yourself waking up sore, or tossing and turning to get comfortable, your mattress may be to blame. Shop for a mattress every few years to ensure that you are sleeping on the most comfortable mattress for your body. While many people believe that a firm mattress is best for the back, it may be that a softer and more comfortable mattress can lead to a better night's sleep for you.
While the age of your mattress can determine that it's time to buy a new one, other signs indicate that's it's time for a new bed. If you find areas of visible wear and tear, you can feel the coils when you lie on the bed or the metal coils are sticking through the mattress, the mattress needs to be replaced. Also consider a new mattress if your current mattress is worn unevenly and flipping doesn't help, or if you roll into the middle of the bed while you are sleeping because of sagging. If the mattress --- not the bed frame --- squeaks or makes other noises when you sit or lie on it, the coils could be wearing out, meaning you need a new mattress.
In some cases, mattresses should be replaced regardless of their age or comfort. If your mattress is water damaged beyond simple spills, it can harbor mold and mildew, which can cause health problems if you breathe them in every time you sleep on the mattress. If your mattress has harbored pests, such as bedbugs, you do not necessarily need to replace the mattress. You can purchase a mattress casing that will prevent pests from escaping and eventually kill all existing bugs and eggs. However, for peace of mind, you may wish to replace the mattress instead.