It has to do with the brand of fuel and whether it has oxidation inhibitors within it's chemical content. Now because the fuel is organic it tends to rapidly change its chemical composition overtime creating a variable of different bonds. Without these life extensions, for a lack of better words the gas would be crap in days.
Depending on which brand you are using and what fuel it was mixed with and whether it has a high content of oxidation inhibitors will obviously help as well. These inhibitors add shelf life to your fuel and when stored properly, meaning no UV light your fuel can be spared with a greater length of time. These inhibitors are often non-existent in race fuel.
A fresh, unopened steel can of Sunoco-112 or VP-C12 may be safely stored (at cool temperatures) for up to 12 months and is recommended that it be used within 3 weeks after opening. Sort of scary to think the ambient air can inflict such pain upon expensive fuel.
I personally talked to a rep at Sunoco Racing Fuels 3 weeks ago over lunch on the issues of storing race gas, and something he mentioned was to never purchase more than you can utilize in a 2 week period otherwise it goes to waste. This just goes to show again that it doesn't last long when exposed to the air and UV light.
Now back to the specifics of your question. If it were my sound investment I would consider running the tanks dry when she sat for more than a month. Granted I've run my boat with old gas before but who knows what sort of havoc I was playing on my carbs and induction system, let alone fuel pump and filter.
The major reason why you've gotten so many different responses is entirely because every gasoline or fuel is blended differently. 76 110-Gas have alot of additives to meet street legal gasoline specs and might last longer than say Trick or VPs-C12.
Wow...I think I'll step away from the coffee cup right now