You've made a big investment in a mattress that should provide you with many nights of comfortable sleep if you care for it properly. Mattress maintenance is fairly minimal. Essentially all that's required is flipping and/or rotating it regularly and protecting it from moisture and stains. Following these guidelines will keep your mattress in good condition for years to come.
If you have a two-sided mattress, one way to increase its longevity is to flip and rotate it regularly. This is especially important in its first few years. Follow the manufacturers’ recommendation for how often to flip your two-sided mattress, but a good rule of thumb is to flip and rotate every 3 months during the first year and every 6 months thereafter. Note that flipping a full-sized or larger mattress is generally a two-person job! Also note that if your mattress has handles on the sides, they’re actually not made to support the flipping of a heavy mattress. Get a good grip on the sides of the mattress to turn it over, rather than attempting to drag it by the handles.
Many mattresses sold today are no-flip mattress. This means that only one side of the mattress is designed as a sleep surface, usually with layers of padding made from materials like memory foam and latex that are designed to provide comfort and resist compacting and forming body impressions. These mattresses can’t be flipped, but since partners are often of different weights and since the upper body generally weighs more than the lower body, no-flip mattresses should still be rotated head-to-toe in order to delay the onset of body impressions.
Along with your new mattress, you’ll want to purchase a moisture-resistant mattress protector that will help protect the surface of your mattress and keep it clean and free of moisture and stains. The body loses a lot of water in the form of sweat during the night, and you’ll want to protect the surface of your mattress from this moisture, particularly as surface stains may invalidate your warranty.
Mattress protectors are designed to go directly on the mattress, underneath the fitted sheet. Some mattress protectors come with a layer of quilted padding. Others are designed to keep out mites and bedbugs. Some cover the top and sides of the mattress much like a fitted sheet, while others encase the mattress completely and close with a zipper. Protectors, sometimes also called "covers," can be made of waterproof materials like vinyl (recommended if incontinence is an issue) or of breathable fabrics like cotton. Choose a mattress protector whose construction and materials suit your needs. Mattress depths vary, so check to be sure the cover you choose will fit the size and the depth of your mattress.
If your mattress has a removable washable cover, follow the manufacturer’s recommendations for care and cleaning.