In the metro Atlanta area where I live, all gasoline sold contains at least 10% ethanol, and even adding a fuel stabilizer does not help much. So, I always fully drain the tank and carburetor on my mower at the end of the season, and dump leftover fuel in the can into my car's tank. I then fill up 2 x 5 gallon cans with stabilizer to run a generator during power failures / ice storms. Start over with fresh fuel in the spring. If I could buy some non-ethanol fuel without (driving to a marina or airport and paying $5 a gallon, for it) I'd suspect treating it with fuel stabilizer would do just fine and last for a least six to nine months with no issues.