The main problem with cleaning on site is that the tech may not identify the rug properly. IF you have a knowledge of rugs and IF you have a clear understanding of the proper method for each rug, then why not clean SOME rugs on site. We know and make sure the customer knows that it will be a maintenance cleaning and not a restoration cleaning. The maintenance cleaning should be around half the restoration charge.
I have maintenance cleaned rugs on site for years. IF you properly vacuum, then a simple encapsulation or extraction cleaning is fine. Years ago we did a rug class in Salt Lake and I brought one of my heavy use Karastan rugs to the class. Doug and Scott did a great job with a pit wash method and it was the cleanest it had ever been. When I brought the rug back to the house, I told no one of its great cleaning, they just knew it had been cleaned. No one noticed how much cleaner it was than my previous encapsulation or extraction cleaning.
The conclusion of the matter is that most customers want their rugs cleaner. Choosing between a good, better or best cleaning is probably more of a function of economics than reaching a high standard of cleaning. This is especially true when the $4.00 per sq. ft. cleaning charge is almost half of the purchase price of the rug being cleaned. Our society is on the verge of becoming a throw away society. Many buy a rug knowing that they will replace it in five years sometimes meaning they will not clean it during its entire use in the house. This is a logical decision especially if they need to pay $4.00 a foot for a restorative cleaning on a rug they plan to replace in the next few years.