I only have enough gas for about 2 days. And lots of empty cans my husband won’t let us fill. Grrr.
The problem with gas is that it does go "stale" - that is, it is not as good after long term storage as it is fresh. Now, 2 things that can help is using gas stabilizer (Sta-Bil is one brand) to help preserve it. If you do keep a larger amount of gas stored, rotate the supply so that you use up the oldest first (use it in the mower or whatever in normal times).
Another important thing to do is not leave old gas in the fuel system of a motor - my generator has a gas cutoff valve, and after I test run it, I turn the gas off and let it run out rather than leaving gas in all the hoses and carburetor. Why? Because it tends to turn to sludge and varnish, and will clog and gum up the works. At least in the tank, it won't be as harmful.
My riding tractor barely started last spring because I left old gas in the system. And my walk-behind mower's fuel system was all gummed up because of stale gas from the previous mowing season.