How do you ensure that the gasoline that you purchase is the best quality?

You cannot insure anything about the crap at the pump other than buying 55 gals of fuel from a known reseller. Even the amount of chemicals we have to add to “stabilize” just to last 2-3 months.

There are reports out on you tube that claim even octain is a lie here in the US.
We pay more for higher octain fuel but it is the same as the cheap stuff. Honestly my car does not ping on cheap or high octain with over 10-1 ratio.