Cleaning frequency depends a lot on usage. If carpets and furnishings are located in high traffic areas, like family rooms, hallways, stairs, etc, then cleaning is required more often than if they are located in lower traffic areas, such as bedrooms, or more formal living areas. Often, we suggest to our customers that they at least clean the "traffic areas" of a lightly soiled room. The expense is less than that of a full wall-to-wall cleaning. Alternating cleanings between "wall-to-wall" and "traffic areas only" saves time and money, but offers one other benefit - we'll be in your home a little more often, and we'll be able to take care of those little spots and areas of light soiling on the rest of the furniture and carpets while we're there. Often there's no charge - or only a small charge - for these "while-you're-here-you-might-as-well"'s. The net result is that, when we leave, the whole house can look great without your actually having had to pay for more than what you needed. Our number one goal is to make sure your home or office looks as good as it can as often as it can! Bottom line answer: Most carpets should be cleaned at least once yearly. And by the way, you shouldn't wait for things to look noticeably soiled before cleaning them - that may be too late.