Mattresses are not the easy things to take care of, you can hardly just chuck them in the washing machine when they get dirty. However, you should attempt to keep them as clean and as well maintained as possible.
You should rotate and vacuum your mattress ever three to six months. Any longer than this and you risk doing permanent damage to your mattress through either mildew damage or structural pressure. When you rotate and vacuum you should look out for any mildew or mould that may be growing. By rotating it, you are ensuring that it will not develop ruts or grooves prematurely. When you rotate it, it is a good idea to leave it to air for the day. This will help to dry it out, thus preventing mould and mildew from growing. When vacuuming it, you need to be as thorough as possible. Don’t just give the mattress a once over, leave the vacuum on each spot for between five to ten seconds to ensure that the vacuum is able to pull all the dust from that section. If you have a specialist nozzle, then use it.
If your mattress has a removeable cover then this should be washed frequently.