i don't clean my sand bed at all, coz i am lazy. and i don't want to disturb the pods and small sea stars i have in there. i clean my refugium a little bit every week; that includes harvesting macroalgaes, rinsing the mechenical filters, etc.
i spend on average 2-3 hours a week maintaining my tanks (i have 2) right now but there was a lot of effort setting things up and getting them to this point.
i feed my fish (13 of them) plenty of food and my nitrates stay at 10-15. so i think it works.