The Dyson cleaners do not lose suction in the same way as a bagged cleaner does, or indeed other bagless cleaner. There has been a good deal of testing, reports, and court cases over this issue not to mention complaints about advertisements from rival manufacturers and indeed Dyson over the rival's advertisements about all sorts of claims being made. But even so, a Dyson will lose power if the filters are not kept clean and free from the dust which naturally escapes from the cyclone tank. As I understand it, the no loss of suction aspect refers only to the method used to capture what the cleaner picks up and not the filtration. I have found that it does take a very long time for the filters in a Dyson to become problematic, so it is not really a big deal I think, not like other bagless cleaners which utilise the filter as a way of keeping the entire contents of the tank in the tank.