They use harsh, cheap, and even dangerous cleaning agents leaving toxic amount of residue in your home. Some of those residues are not safe for your pets, much less your children. Chemicals these un-educated cleaners use strip the life from the carpet fibers adding years to the wear age. Plus these cleaners do not pull out all the embedded soil debris that ends up at the lower part of the fibers which will cause your carpet to wear faster. This means you are going to have to replace your carpets sooner (big bucks). So not only will you pay more in the long run by going with "cheaper cleaners" you won't be enjoying the benefits of a great looking carpet and a safe HEALTHY home.