I'm in California, no ethanol free gas anywhere close, and the biggest problem I've run into with our ethanol gas is eating older fuel lines. I run stabil in smaller equipment and will drain everything if it's going out of service for a while. If it gets regular use, gas/moisture corrosion isn't an issue. With tractors, etc., the key is draining the fuel system if it's not in use for a while, and being mindful of the last fill. If the gas is going to sit in the tank for 6 months, get it out and use it in something else. The ethanol attracts water, and older tanks/carbs are notorious for condensation as well. Bad combos.
Just did a quickie rebuild on a Marvel TSX-603 again last night after doing it about a year ago. Why? Because the owner decided to use old gas, leave it in the tank, line, carb, and it ate through top of the old fuel line at the carb inlet, which also allowed water into the carb as well. Discovered a bunch of gooey rubber all the way to the seat, and the inlet passage and bowl had a nice rusty finish to it, along with a proper water/rust line. He's off to buy new fuel line and filter today. Hopefully everything is now good.
Diesel is also a problem. Lubricity just isn't there anymore since 2005ish ULSD. I run Stanadyne lubricity formula in anything pre-2010ish. I haven't done enough research into the renewable diesel or B5/20 blends, so I can't comment there. My truck and tractors aren't new enough to handle the blends. I just run diesel #2 with Standyne.