"Fill, premium, cash". Those are the instructions I give the attendant (Oregon is a no-self-serve state). Daily drivers at 285k & 303k miles on original motors. Camper hauler has a new 383 because I wanted more power than the original 350 provided, not because the 350 wore out. I believe in treating them right with regular maintenance, quality parts when needed, and good gas.
That way when I put the right foot on the floor, there are no questions in my mind that the vehicle is prepared to handle it.
-Eric