It is also important to properly maintain your car. “If your car is in bad shape, it costs more on fuel and repair costs increase quickly,” says Larkin. “Something as simple as not changing the oil regularly makes the engine work harder, and it uses more gas.” It’s also important, he says, to avoid bad driving habits such as speeding or running at a red light.

As for avoiding higher (and more expensive) gas qualities, that could be a mistake. “It depends on your car,” Larkin says. “Some cars, like performance cars where the pistons are bigger, use a higher octane rating. Running an 87 octane (regular gasoline) in a car like this can cause knocking and creating excessive engine wear.The best thing to do is to look in your manual and see what rating the car manufacturer recommends.

Is it better to leave your car idling or to turn it off and start it again? “Turn off the engine and restart it,” Larkin explains. “The amount of fuel you save by shutting off the engine is maybe a third of the fuel you would use if you left the engine idling.”

Larkin says that as cars age, they become less efficient “simply because of engine wear. Changing the oil regularly, ensuring the brakes are serviced regularly, and making sure the tires are properly inflated can save you a mile or two per gallon.

Finally, even if it’s painful, try not to let your gas gauge hover around E. “The fuel pump has to work harder,” Larkin says, “and any sediment on the bottom of the tank could get sucked into the filter mechanism.”