Dirty carpets can be unhealthy for the people living in the home, particularly those who have allergies, so it's important to have them cleaned regularly; simply vacuuming once or twice a week isn't enough. Carpet cleaning should be done by a professional carpet cleaning service at least once a year to remove grime and help extend the life of your carpet. Most carpet manufacturers recommend professional steam cleaning, which penetrates deep into the carpet fibers and lifts out both dirt and the pollutants that get tracked inside.