I sort of try to imitate the wild and be sporadic - or maybe I am just lazy! I usually skip a couple days a week but also I usually feed twice a day once or twice a week, and the rest of the days just once. That said, I have some tanks where the fish really need to be fed pretty regularly - my darters get skinny if I don't feed often enough, as do my Elephantnose fish. My big cichlids seem to get a lot more aggressive if they skip more than one day in a row being fed. Also obviously if I am trying to growout babies fast they need lots of feeding.