Wow, answers all over the place. Gas is "good" for about 6 months. Your car and "run on it" maybe even a couple years. I've had poor luck with Stabil and Sea Foam isn't snake oil... old technology, but useful. My advice? change all gas over 6 months
Oh...I don't know.
I can't definitively answer the question "how long with Stabil last" but I've witnessed Seafoam perform small miracles. That's what's in my b.o.a.t. for the Winter.
On an aside note, I run my chain saw out of gas after every use because I seldom use it.
