PRI-D

I believe ?

Supreme grade gasoline stores better/longer than regular since it has more stabilizers formulated into it. Toss that in when you are weighing all your variables.

[This is what farmers in my area indicate. They have equiptment that sits all but 3 wks a year, during which it is often used 16+ hrs a day for harvest. (These days, farmers have to work both hard and smart to make it!)]

Due to an acute attack of stupidity, I had a 1996 Honda Civic in my driveway for nearly two years before I got around to selling it. By then the alternator had frozen and it had to go to the shop for repair and checkout.

When it was time to start the engine everything started up fine, in spite of the fact that the gasoline in the tank had been there for about 21 months. No stabilizer had been used.

This is NOT a recommendation. I add Sta-Bil to the 2.5 gallon tank I used for the mower and snow-thrower. That is not so much for the gas in the storage tank but for the gas still in the mower/thrower tank during the off-season.