If your gas sits around for long periods of time, add Stabil to it when you first buy it. That goes for E-10 and non-ethanol fuel.
I've had E-10 for lawn mowers and whatnot last over a year in gas cans without separating or gunking stuff up , but I wouldn't put it in a vehicle. Mixing "bad gas" with lots of fresh gas doesn't suddenly make the bad stuff good.
If you're buying non-ethanol fuel, a year or so old is ok if it's in a sealed can.
