All this talk of filling when still half full reminds me that we would lose money doing that. Here in Ohio we do Kroger Fuel points. We get them for buying groceries and gift cards. If you have 1000 points you get $1.00 off the next fill-up. So obviously you want to use as much gas as possible to save the most money. I have a Ford Escape that is only a year old. I generally cannot get more than 14 gallons in it, but take over extra gas cans for adding to the car later, or for the tractor, etc. This way I usually can get about 20 gallons total. So if were to only fill the tank when half full I would only save about $10.00 or less depending on the cans. The $1.00 is PER Usage. If you pump 5 gallons, your $1.00 is used up.
Greg