I'm not arguing and I plan on running premium, but it's more than pennies for me. Premium is 18% more expensive where I filled my car yesterday, so driving 20K miles per year at $2.39 for regular (17.0 mpg) and $2.82 for premium (17.6 mpg) the difference calculates to $392 annually. I plan on filling at Costco (top tier) whenever possible, the price difference from regular to premium is less there. Unfortunately there is no Costco in my town, so there will be many fillups at other stations especially with the thimble size tank in the Scab I ordered.
Octane is basically the burn rate of the fuel. On regular the engine's knock sensor will retard timing to reduce detonation which is why there is a power and mileage decrease, but I can't see it causing any harm.