where i'm at...in CT, there's 92...matter of fact...i just filled up last night...91,92, 93...can't really tell the difference...although on one occasion, pumped 91 at NJ, not long after, you can hear valve tapping/knocking...hated it...had to burn it down...in any case...i get around 200 miles between fill ups...

 

One other thing to consider. Running long distance I always buy the highest octane fuel. Why? In case the next stop has really low octane fuel and I have no choice but to mix it in. I have run into this running rural areas.

I do get 1-3 MPG better mileage with the higher octane.

 

In Texas we have 93 and when we hit surrounding states I hate it when they only have 91. It's more of a preference thing but I like 93 much better.

 

I get worse mpg on premium. Nearly always have run 87. On some trips have tried the higher octane due to altitude, and a couple times by accident due to hose placement at the pump. Not a matter of costs, just not necessary. Only a stage 1, stock low compression and doesn't ping with 87. I also don't run that oil with the little HD symbols floating around in it.