Yep, and now that most cheap economy cars are turbocharged now they require higher octane fuel to meet their published MPG rating. So it isn't just about cheaper gas for cheaper cars. The manufacturers account for this, and build them so they run on lower octane fuel anyway knowing how careless the average carowner is. But it isn't optimal, and you may even be losing more money this way through loss of efficiency. But using "premium" on a car rated for 87 octane is a complete waste of money as nothing is gained by it. Back in the pre-internet days, people would spread some weird urban myths about gas, like thinking premium fuel would clean your engine or some other such nonsense.