Don Farrall/Getty ImagesExperts say you should keep your gas tank at least a quarter full at all times. AdvertisementAdvertisementYou could also get debris stuck in your fuel pump by running your tank too low. If you're constantly running your gas tank dry, the fuel pump could be overheating, which will cause it to wear out prematurely. Now that you know that driving on empty is actually bad for your car, it should be easier to break the habit. That said, if you find yourself in a situation where you're running low, you won't ruin your car if it's only the first or second time it happens.