Question re storing gasoline for use in a generator

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I got an emergency backup generator and I've never used it yet.

I've read that gasoline goes bad after being stored for too long and you shouldn't run old gasoline in an engine or generator, I don't know how true this is.

I figure about once a year I'll end up using the generator.

What is the best thing to do? I could empty the can of gasoline into my car gas tank every few months and refill the can with fresh gasoline, I don't really want to do this to my car engine.

Or just keep the old gas and run it in the generator anyways?