Well, professionals really make a big difference. Remember when you insisted on changing the car battery yourself? Remember how sad it was to write that check to the mechanic knowing it could have been avoided? Ok, so carpet cleaning isn't exactly car maintenance, but it is a maintenance of another kind. Just like cars must be inspected, carpets must be cleaned. It is the nature of the beast. Carpets in top form protect you from any number of potentially hazardous indoor pathogens. They accomplish this by trapping and latching onto all kinds of bacteria, allergens, dust, etc.