Gas will still work after a year in a tank. But it won't have as much pep as when it was new. How do I know? I own a motorcycle. It sat for a year, and then I decided to ride it. But it wouldn't start. Just wouldn't fire. I did one thing -- I syphoned the gas out of the gas tank, and put new gas into the tank. It started on the first touch of the starter button. I've used gas more than a year old in lawnmowers, and they will run on it, but probably not with as much pep as they would have had with fresh gas. Gasoline is a very perishable substance. The whole "Road Warrior" scenario is ridiculous, where you see them trying to get gas out of tankers when it's been sitting for years.