Spent the weekend shampooing about 1000 sq. ft. of old carpeting. At the end concluded that it didn’t need shampoo. It needed new flooring.
I will say that the Rug Doctor kicked butt. Buy some extra shampoo however, because it’s primary job seems to be to put out and suck back gallons of soapy water on the carpet. About 4 gallons in 10 minutes. But it’s one kickin’ shampooer. Rented from Loew’s.