I agree, modern petrol, or gas as the yanks call it, does go off a lot quicker than it used to.
When new, first Hondas to need draining if stood were CX500 & CB750/900 twin cam(79+) and it was usualy anything over 8 days drain the carbs, what was in the tank stayed OK though. Never did figure out why just drained them in the workshop on pre- customer checkover