I have a stand alone gen with it's own fuel supply (gas)
I have/do fill it with whatever is available (12 gal) and then properly dose it with Seafoam or Stabil
Then at least once a month run it for 30 minutes under at least 50% load
I have 2 gas cans in garage....one 2.5 gal and one 5 gal
Again ...whatever fuel is available and again good dose of Seafoam or Stabil
Gas is used in walk behind lawnmower/riding mowing and in chain saws
Only issue starting/running was due to a non operating choke on walk behind mower (twig was stuck in choke slide)