Again its almost a matter of watching your tank. If the water is clean and the intakes are not clogged up with algae or plant debris, then don't worry about it. I rarely ever rinse my whole filter anymore. Once every other week I'll take the top off my AC-Mini on my 10gal, take out the bottom sponge which I use for mechanical filtration, squeeze it out in some removed tank water and put it back, that's it. The top sponge is my biological filtration and I never squeeze it out, maybe once a year swish it gently in some removed tank water, but that's all (I don't use any carbon on a normal basis). My eheims on my 34gal and 77gal I do even less often, once every 2/3 months, taking into account there's nothing wrong with the water.