People who talk about using lower grades of fuel are -

WAAAY BEHIND THE TIMES !!!!

I have emailed and written to Consumer Reports several times - challenging them to explain how engine management responds when a knock is sensed - they have never contacted me back. They tell people not to worry about using low octane fuel - the knock sensor will take care of it (if it is working!). The explanation that I have read is that the first action is to add more fuel to cool the combustion chambers. Changing timing will not work quickly as the ignition is already behind combustion.

One thing that they do not consider is the numbers as they relate to fuel prices VS mileage figures.

The percentage of prices between regular and premium are MUCH smaller that when fuel was 30 cents a gallon.

In a car that gets 20 MPG, one MPG is 20%!

Engine management is much different as well - Did auto engines manage themselves 40 years ago?

I contend that using lower octane uses more fuel and allowing the engine management system to do its thing properly is well worth the relatively small extra cost.

If you take the mileage that you get (actual or your estimate) and divide that into the miles that you drive in a year, then price it for a year for premium and regular, how many extra dollars do you spend?

For the year? for a week? per mile?

Besides, your engine will love you.