You would not wear the same pair of socks for days without washing them, would you? Then why wouldn't you have your carpets cleaned regularly? You clean your hardwood and ceramic floors more than once a year. So you should have your carpet professionally cleaned at minimum every 12 - 18 months using hot water extraction by a professional company. Store bought residential carpet machines will work for spills and occasional cleaning. However, professional hot water extraction will pull the dirt out of your carpet that your vacuum or residential carpet cleaning machine simply is not powerful enough to get. Keeping your carpet free from debris is not only healthier, it will prolong the life of your carpet. Most carpet warranties require annual professional carpet cleaning with hot water extraction to keep the warranty in force.
For more information you can check out this helpful link: