And I might add while I am at it for the people who have not studied the matter, watching the fuel is an actual time consuming job in itself. We have too much power to overlook this. Sure, we have knock sensors that pick up on detonation, but once it happens, you cannot take it back. It is cumulative to the fatigue of just about everything that goes up and down and around in an engine. What you do now could come back to bite in 2 years. Like tapping on a block of ice with a ball peen hammer, it will look fine and go for a long time, and then without notice it will abruptly split in 2 pieces. Not tomorrow, or even in 6 months or a year, or 3 years...but eventually.
Keep in mind 10% typical unleaded goes away much faster than std no alcohol gasoline. When you pull the car out of storage in the spring that gas is most likely shot, but will seem to drive around fine. Run it low, mix in a couple gallons of good stuff, take it easy and repeat the process a couple or 3 times. I found that the 93 around here will start to deteriorate in a month, and it pretty much on its way to being shot in 3 months.
There are too many variables to consider when you fill up at an unknown gas station. How long has the premium been sitting in their tanks ? It doesn't get used as much as 87 don't forget. And then every once in a while you get a greedy station owner that cheats on the octane, or the tanker driver is new and put the 87 in the 93 tank which happened a couple of times in 10 years around here. Or the guy who mixes the fuel at the distributor has a bad hangover.....
It is a job in itself watching the fuel, and if you like your car and want to keep everything optimum, stay on top of it. Always have an ST knock readout where you can see it is my advice, and that is written in stone.
From someone who has burned pistons, blown headgaskets, made more mistakes than 5 people in the early years and created a lot of my own grief. I didn't have mentors or the internet or much to go by in those days.
When your wallet starts to hurt, it drives a few points home. But an education has its price....