In general, gasoline and diesel can be stored for 6 months to 1 year without significant degradation if they are stored in a clean, sealed, and dry container or tank, away from sunlight, heat, and sources of ignition. However, fuel that is exposed to oxygen, moisture, or contaminants can deteriorate more quickly, resulting in reduced quality, lower octane rating, and increased levels of sediments or sludge.

So yeah, the trope of hopping in an abandoned car after the zombie apocalypse does not work 😂

I bought a gasoline powered motor home that had been sitting for about 5 years unused.

I tried to fill the tank with fresh gas and hope it would offset the bad gas.

Although I did drive it some, it was hard to start and ran poorly. Eventually I just had to replace the ~~diesel~~ fuel pumps and get the injectors cleaned. Lot of work. In the end I wished I had just drained the tank and put fresh gas in before anything else.