We've all had this experience one time or another: you're late for an appointment and realize that your gas tank is no empty, rather than taking the time to fill it up you just put enough to hold you over. For some of us this is more than just a rare occurence...for some, it's the method we use at the pumps every time we visit them. 

Which brings us to our question: Should you always fill your gas tank full rather than adding just a little each time we visit the pump?