Ensure that you hire a trained professional in the field as there are many who will use incorrect procedures,  which can have an adverse affect on your carpet.  For example leaving detergent residue on the carpet will actually  increase the probability of the carpet getting dirtier than it was before it was cleaned. This does not occur hiring a trained technician, so beware of less effective alternatives.

How often should carpets be cleaned

One of the main reasons for  cleaning carpets is dirt not just because they look so bad but because dirty carpets will wear out the carpets faster.  The wear is caused by dirt grinding into fibres causing them to fray, unwind an mat together. 

In order to defend against this, carpets should be regularly cleaned  by professionals  once to twice every 12 - 18 months but this depends a lot on the environment where the carpets are situated. Environmental conditions include but are not limited to the following: smoking, children, pets, humidity, temperature.

Carpet cleaning is one of the most important aspects of maintaining a safe, healthy environment for living, play, or work.