I’ve had 2 boats since 1986 that stayed on water all summer and never cleaned the tank. For that mater I never changed the fuel filter either
Most tanks have a pickup that does not reach the bottom, with a screen. So even if a little dirt is in there it’s not a problem.
And I’d say the bigger the tank the less likely it could ever be a problem. Largest tank I had was 35 gallon.
Never cleaned tanks in lawn mowers or rotor tillers etc. my rototiller is 30 ish years old and I can see dirt in there for as long as I can remember.