As someone else already mentioned, small amounts can go bad sooner than if the tank is full. I think it is partially due to the air in the tank, and the moisture in the air, so it's always advisable to keep the tank full. Stabilizer is no doubt a good thing to add to some of these vehicles that aren't driven a lot.
I have to believe that warm weather probably makes it go bad sooner too. I once had a boat (89 gallon fuel tank) sit for 2 years in Wyoming (read: cooold weather). I had the tank full, with NO stabilizer in it. I routinely let it set for 8 months like that, but circumstances beyond my control stretched it out to 2 years that time. When I went to get the boat, it was fine, and the Rochester 4 bbl on it didn't even have any problems. I figured I would be looking for a place to put a bunch of bad gas, but lucked out. Bottom line, don't worry about it. If it runs crappy when you get it running, take the carb apart and clean it out, as the gas will most certainly have evaporated out of it and will leave some residue. Old leaded gas was much worse about that than unleaded.
"Get your facts straight first, then you can distort them as much as you wish"!!
1965 Fastback, Sunlit Gold, I6, T-5, Pertronix, CAA AC, SSBC frt discs