The machines you hire are small and not properly maintained. They don’t clean deep down as they lack the power. They are very labour intensive, as the tank is small and you are forever filling and emptying it. You can easily over wet your carpet running the risk of damaging it. The chemicals you buy to do the job may not be the correct PH for your carpet. Last of all it takes a lot of time to pick up and drop off the machine, and clean the carpets. It will actually cost you quite a bit in the long run as you have to buy chemicals and defoamers which may have left overs you may never use again.