this is what i say
"to clean reasonably with a rug doctor you have to clean first then do it again about 3 times with just water to rinse out the cleaning fluid. if you don't rinse the cleaning solution out, the carpet will have sticky soap in it that will attract dirt really quickly, also by time youve finished your 3rd rince your carpet will be soaking wet for about 3 days, as the rug doctor only cleans the top fibres, once you walk on it wet (and you'll have to unless your going away) the deep down soil will blot up to the surface and your carpet wont look much better, ive just cleaned a house where a women has been using a rug doctor, she told me the first time she used it, the results were ok, but she noticed exactly what i told you, it was getting dirty really quickly, so she did it again a few months later, then again a month later, then she realised and called us in, we rinsed all the built up dirt out and the sticky cleaning solution and she won't need it cleaning for at least another year, we don't have a £15000 machine in our van for nothing"
i usually get the job,
if not there and then, i get it 3 months down the line from a red faced customer.
tolerence, patience, education, kerrrching
works for me.
derek