The Ergorapido has filters to clean the air, and collect any dust, so it doesnt get blown out into the air again. Naturallly, these filters get get dirty when you used them. And after a while they will even start to fill with small particles – and this clogging will reduce the suction power.
There is a built in function, that lets you easily clean the filter, every time you empty the dust bin. The Snap Clean Filter. You can see it describer here, on an older model. The functionality is the same on all new models as well.
However, it does make sense to replace the filters every now and then to maintain the best performance of the Ergorapido. You can find on on e.g. Amazon. Just search for Electrolux EL 018, Ergorapido EF144, AEG AEF 144