I have fuel that is years old[bought from a friends estate that had been stored for unknown years as he aquired it mostly thru sales of estates] and is stored in unheated garage in Wisconsin. I still use all the time as if it were fresh. It works just as good as any other. I don't think that there is any such thing as fuel getting old from one year to the next as long it is stored in cool, dark conditions and tightly sealed. I have fuel left in my flight box from last year that I intend to go right on using just as if it were new.