i have never vac'd the sand bed.
not in my last tank which ran for 10+ years before divorce/tear down.
not in this one which got wet august 2018.
i seeded the sand bed with spaghetti and bristle worms at setup.
i keep minimum of 5 tigers and probably now have over 100+ nassarius snails from all the repro going on.
why do i want to remove a food source for all those happy critters.
also: i have zero live/dry rock in my tank.
i never run a skimmer. algae scrubber only.
kinda unorthodox i know. but it works.