[taubek]

Yeah, fuel degrades over time. There are different numbers out there. Exxon [1] says up to six months. "In general, gasoline should be used within a month of purchase. When the engine will not be used for an extended period of time, it’s best to drain the fuel tank and then run the engine until it stalls. If you choose to store gasoline and follow proper storage guidelines, the gasoline can be expected to remain of good quality for at least six months."

https://www.exxon.com/en/gasoline-safety-storage

[bruce511]

While I'm sure this is good advice, anecdotally I filled up a car with gas just as lockdown started, and then didn't use that car much for the next two years. Still seemed to run fine when I sold it this year.

More: this was a 1997 car with gas not diesel.