Hi
Drying times are very difficult to state accurately as it depends on a number of factors including carpet type, humidity, ventilation, type of cleaning process and individual technique. For example, a wool carpet cleaned on a hot summers day with the windows open and cleaned with a bonnet mop is likely to be dried by the time you've written the bill! I do think, however, that because drying times are so important to customers, there are carpet cleaners out there who tend to err on the side of optimism!
Turbo dryers can often make a big difference if you dont already use them!