I don't know if I agree with all that but in my motorcycle I let it sit for only 2 weeks and had issues with water separation
Water is getting into that bike's fuel system somehow.
I leave E10 gas in my riding mower all winter and never have a problem. I store it in my garage, it's not outside getting rained on. Why would I store a piece of equipment that would cost over $2000 to replace outside??? I see people who leave their riding mowers and other OPE out in the rain all the time. Guess they have money to burn.