Replacing a mattress is expensive, so it makes sense to ensure your mattress lasts as long as possible. These tips won't make your mattress last forever, but they will decrease the rate at which it becomes worn, so you can hopefully keep it around for a few more years.
Avoid non-breathable mattress covers.
You might think that encasing your mattress in a plastic cover to keep it clean would extend its life. However, if the cover you choose is not breathable, it may trap moisture in near your mattress and lead to molding. If you choose to use a protective mattress cover, look for one with vented panels, so moist air does not get trapped inside. This is especially important if you live in a humid environment.
Give the kids another place to jump.
Jumping and bouncing on a mattress can damage the springs, leading to a lopsided, lumpy, overly soft mattress that needs to be replaced. Make sure your kids know not to jump on your mattress or on their own. This is more easily accomplished if you give them another place to jump -- like a trampoline in the yard. If you have an old mattress you don't use anymore, you could even set it up in a spare room solely for the kids to jump on. Just make sure they know that jumping is only allowed on that one mattress.
Turn the mattress end-over-end regularly.
You probably already know to flip your mattress every few months. However, it's not just side to side that you should be flipping it. By flipping it end over end as well, you're ensuring that the top and bottom portions of the mattress get even wear. This can help prevent sunken in areas, which often form where your shoulders rest, from developing.
Vacuum the mattress.
Dead skin cells, mold spores, and all sorts of other nasty particles find their way onto your mattress -- and then into your mattress if you don't remove them. Vacuum your mattress on a regular basis, using the wand attachment so you can get into all of the little grooves. You'll prevent the mattress from developing smelly, musty odors this way. Even if your mattress is in a cover, you should remove the cover and vacuum it periodically to remove mold spores that were in the air inside the cover.
It takes a bit of time and energy to care for a mattress properly. However, if you put in the time, you can save yourself a bundle of money by not having to replace your mattress as soon.