My 55 gallon tank only gets a cleaning and water change about once a week, but the smaller tanks usually get cleaned more often, depending on how many fish they contain. My fry tanks get daily and sometimes twice daily water changes, depending on how crowded they are and what I'm feeding them.
I don't have a set schedule, and because my tanks have a number of different size filters on them, that will influence which ones get more frequent water changes, as well