Definitely add fuel stabilizer to gas cans used to store gas. I had a couple that I didn’t use for years and had no problems with the old gas.
Absolutely. I use the Marine Sta-Bil, and do a double dose. And I buy premium gas, on the theory that if it degrades a little in storage, it’s still pretty good. And I feel better about dumping a little in the cars, on top of a nearly full tank, to use up older stuff. Cars take premium.