Most of us were raised by fine, upstanding citizens who taught us right from wrong, so we all know that high-octane gas is better for your engine than regular gas.

Are you sitting down? Good, because none of that is true anymore. Cars have changed, engineering has improved and premium gas costs 20-30 cents more per gallon for almost no benefit. Let’s look at the myths about high-octane fuel.

Increased Performance—The lore about premium gas is that it improves the performance of the engine. In some high-compression engines, you can get more power out of premium gas, but if you offset it with the extra cost, it’s a wash. If your car feels underpowered, it’s probably not because of the gas. You might want to check with a mechanic.

There is one rare instance where premium can help. If you have a vehicle under a heavy load, like towing a large boat with a small car across the dessert, then premium might help the journey by providing more power. But it won’t help your engine life.

Some engines require premium—There was a time when premium gas was “recommended” by the owner’s manual, but now it’s merely “suggested.” That’s because all engines are designed to work using regular gas with no consequences to the longevity of the engine.

Premium reduces knock and ping—Before 1996, using premium did reduce premature ignition and thus reduced knock and ping. And knock and ping did definitively take years off an engine. But now, engines are equipped with a knock sensor that automatically adjusts the fuel and air to prevent this. So again, only under extreme heavy-load situations will premium will be needed.

If you use premium now, test it out. Try regular for four or five tanks and see if you notice any difference. If not, you can probably save nearly $200 a year by buying regular.