I do keep about 90 US gallons of 90 octane non ethanol stabilized fuel on hand, but I cycle through that as I burn it in the bikes and equipment and keep it replenished.
I'll convert here to Imp. gallons for clarity. Fay's Subaru averages 36 mpg over 14000 miles a year. My little '90 Festiva (Mazda 121) gets 50 mpg over 3000 miles per year. The Triumph Trophy @ 52 mpg, the Guzzi @ 49 mpg, and the old Brits @ 55 mpg get about 11000 miles per year.
So my "fleet" fuel mileage is about 48 mpg, and that's worth a lot of money versus not paying attention to it, or driving gas guzzlers. I could drive less, of course, but I'll save that for when times get bad. Right now, if the gas stations went completely dry, I can go about 5000 miles on what I've got stored and in the vehicles...