I am a fanboy for Briggs & Stratton Fuel Fit. It keeps fuel fresh for up to three years. Since starting to use it I have not had any problems starting my mowers, chainsaws or strimmers. It can be used in non-ethanol or ethanol-containing fuel.
I use stabil in every jug of 89 e free fuel I buy, doesn’t matter if it’s going to be used immediately (currently for grass season) or stored. Cheap insurance.
I’ve had good results with Stabil and Seafoam. Mostly use Seafoam. I don’t like gas sitting long though. If it’s been too long with mix I’ll just use it in my hedge trimmer and blower but unmixed gas will get dumped in the truck before it sits too long. But you’re right, e-free goes stale just like the pump gas.