Fathers of teenagers love to pass down this sage nugget, perhaps recalling all the times they ran on fumes during their wild youth. It turns out to be pretty sound advice, too.

"You always want to keep fuel in it in wintertime because you don't want water to get into your tank, because tanks sweat," says Martin. "When you pull in and out of your home garage, you can get moisture in it just because gas is cold and when you bring it into a warm garage, moisture can build up and sweat. You'll get some definite running issues with that."

Duchene notes there are plenty of practical reasons to run full, as well.

"For instance, let's say you have to borrow a car. You start it up and the gas gauge stays on 'empty.' You might think maybe the gauge is broken," he says. "Face it: A car without gas is no car. If you have an emergency in the middle of the night, you couldn't do anything about it."

What's more, if you get stranded in a blizzard without fuel to run the heater, your miserliness just might cost you your life.

-- Text by Jay MacDonald, illustrations by Brandy Kesl.