As I have stated many times on this web site manufacturers say you should change your mattress every five to seven years. Here I will show you how to keep your mattress longer.
The reason they want you to change your mattress is because after this period of time it becomes contaminated and is attacking your heath. Why then do they offer ten,fifteen or twenty year warranties. The obvious answer is marketing. In today's world springs will outlast upholstery and if you read these warranties carefully you will see this is the majority of what is covered Its that little exclusion about wear that protects them. They also won't cover a stained mattress.
With proper care for your mattress you could possibly exceed the warranty if you purchased good materials initially.
Part of your seasonal cleaning regime should include your mattress. You should first completely strip the bed down to the bare mattress. Wash the sheets and mattress pad or mattress cover(I usually recommend a mattress cover). Follow the instructions on the label for your blanket,comforter,quilt,mattress topper and bed spread for cleaning. If you can let them air out buy hanging them on your cloths line or over an outside railing.Keep them out of the sun if possible.
While you bed is stripped you should remove any stains with a good spot remover. You then can use an inexpensive ultraviolet lamp across the surface for deeper cleaning. Generally just carefully vacuuming the mattress will do. This removes dust mites and other allergens keeping the mattress fresher longer.
If you can flip your mattress you should do it and vacuum again. Next you should turn you boxes 180 degrees so the box will last longer placing you main weight on a different surface.
As I said above I recommend a mattress cover instead of a mattress pad. This cover should be anti allergic,waterproof and should be able to breath. Be careful many of these are not really waterproof.Some like Protect a Bed are waterproof and can breath.
You will find terms and conditions on Mattress Information home page