In 2000 it was a recent development that carpet mills were taking responsibility for the product they sell by involving themselves with proper care after the sale. Shaw Industries is at the front of this movement, and they have become the world's largest manufacturer of carpet. Relatively few carpet mills in the U.S. are not owned by Shaw. So far, manufacturers haven't found a good way of taking varying levels of traffic into account, so their advice is only a set of guidelines. Shaw requires a professional cleaning with the hot water extraction method at LEAST once every two years with the evidence of a receipt to keep their warranty in effect, and recommends a fresh water rinse. Some warranties state every 12 months, some 18. These differences aren’t based on specific carpet or use, but random; it tells you circumstances vary. Check yours! They don't require a fresh water rinse because they realize most people can't get it, at any price.
The fact is, the need for cleaning varies, tremendously. Some homes need cleaning more than once a year, and some might get away with less than once every 2 years. The real indicator that your carpet needs attention is when the high traffic pathways start to look different than the rest of the carpet. The problem is that imbedded dirt you can't vacuum out is causing excess friction, scratching and dulling your carpet in these areas. All manufacturers agree on this point; dirt is abrasive, like sandpaper. While this does promote premature wear, rarely does it ever result in actual worn-out areas such as happens to the knees of blue jeans. Instead, the wear-and-tear results in carpet becoming unsightly; often far too soon, when not maintained properly. Usually carpet doesn't wear out, it "uglies out." (I can treat that too!)
The single most important part of proper maintenance for your carpet is VACUUMING; OFTEN AND WELL. A bad vacuum that gets used is better than a great vacuum that just collects dust. A real timer saver (and carpet-saver) is to vacuum just the high traffic pathways when you don't have time to pick everything up off the floor like you normally might to vacuum. There are 2 important components to a good vacuum: suction and an agitator brush, or beater bar. A 2-stage vacuum motor is much more effective, and central vacuum systems are more effective because they use a 3-stage motor. Oreck doesn't have as much suction, but they were the first to come out with a good agitator brush, and it's light.
The next priority becomes IMMEDIATE pick-up of spots and spills. See my spotting guide.
The need for cleaning is the next priority, but it doesn't necessarily have to be done by a professional, at least not at first. If you're diligent, you'll clean those areas that become visibly affected by traffic as soon as they appear. Manufacturer's recommend doing this with "Capture," considered a dry cleaning product. It's simple to use, no equipment is necessary except a nylon brush, there's no real problem with residue from cleaning, and it's cost effective. Capture won't be effective at all if you've let your carpet go too long, and it won't work forever. A product called "Nylac" can cut through dirt that Capture can't, but the only place I know it's available is Vic's Carpet Warehouse in Nashotah.
While this is better than other do-it-yourself methods, sooner or later the job may become bigger than you want to tackle, or your own efforts will disappoint. Then you know you're ready to hire a professional. The manufacturer's guidelines of cleaning at LEAST once ever year or two (depending on which manufacturer you listen to) assumes you're doing all this diligently. In other words, carpet needs a lot more cleaning than most people think!