When topping off the gasoline in a vehicle that is rarely driven (100 miles/month), is there any advantage in topping it off with a higher octane gasoline?
I've heard stories that the octane of gasoline gets lower the longer it sits. I have no idea if those stories are true. If they are true, it seems reasonable to spend a little more and top off the tank with a higher octane fuel.
But are those stories true? Is it a good idea, in this situation, to top off with a fuel with a higher octane rating than is recommended, with the goal being to restore the fuel to the recommended octane level?