There are many variables involved when determining how ofter to have your carpets professionally cleaned. But the most important factor is how well the carpet is maintained between carpet cleaning. A typical home requires routine cleaning of 6 months to 2 years.
Many home owners opt to have all carpets cleaned once every few years but high traffic zones cleaned every year. This will help reduce traffic lanes and other types of damage done to the carpet. Rarely used rooms such as guest bedrooms and closets should be fine for years with just vacuuming and spotting.
Before setting a schedule it is important to check your carpets warranty if the carpet is newer than 15 years. This information can often be supplied by your flooring retailer. If not you may need to contact the manufacturer. Always discuss your next reschedule with your carpet cleaning technician, but beware of companies that try to push overly frequent schedules. A good rule of thumb is no more than once a year except for very high traffic situations.