Buy one gallon of gas at a time

Well, I advise this, and I am a college kid, yes.

But the reasoning behind it? The fact that you should pay attention to? Are you wondering where it is?

Well, with good reason, I'm sure you do. I drive an automobile that isn't worth a tinker's cuss. Buying a gallon of gas at a time is all I can think of when I'm at the station. Just one, because you don't know when this thing'll end up at your house for the next week.

That's what I'm saying. If you buy gas, and your car is a broke down rusted-out box of shit, buy a gallon at a time. Why would you want to waste the extra $1.50 per if you don't get to take it anywhere?

Buying one gallon of gas at a time is typically a poor idea (filling up is typically a poor idea as well). You could easily get stuck some place, but that is not the main concern of the poor. You can get optimal efficiency out of your car by adhereing to several maintance and operating principles.

• Don't fill the tank: You add extra unnecessary weight when carrying around 12-20 gallons of gas (that times about 8 or more pounds per gallon is a lot of extra weight, compared to half of a tank.)
• Don't go out of your way to get gas: Usually, driving off of a highway and back on is bad, if you only put a few gallons in at a time. If gas is "on your way" that's fine, but don't keep yourself low on gas because you will gradually spend money on your trips to and from the gas station.
• Keep your tires well inflated: Keeping your tires well inflated will give you 5% better gas milage, as it reduces the drag on your car. Also, keeping them clean and free of sand and debris can make them grip better, and generally more safe. Letting tires wear down can be dangerous in certain conditions, and destructive over time. Also, get rid of the snow tires as soon as possible. It's better for the road, and your milage.
• Use your vents instead of the windows: If you are using a "free" cooling mechanism, using vents can keep your car more aerodynamic than having the windows open, and thus you will do about 5% better on gas on the highway.
• Don't use power windows, locks, sunroof, etc very often: This will make the engine work harder when you are using it, and thus it will suck up more gas.
• Drive the speed limit: I know it hurts, but the speed limit is the way it is for safety and fuel efficiency purposes. Most cars will do about 20% better on fuel at 55-65 than at 75 or higher. It's a sad reality, but the people who designed the highway know what's best for you, even if you are in a hurry. This is a noticable difference when driving all day, or over a long distance.
• Read your owner's manual or contact the dealer: There are plenty of ways to get optimal performance out of a car, if you simply listen to the people who built it. They know what is best for their baby, so crack open the manual, or drop a call to a well respected dealer for your type of car.
• Be smarter about braking: My dad hates to brake; he tries to coast everywhere. Why? Because in gas-powered cars, breaking is lost energy (in hybrids, breaking recharges the battery by recapturing motion). You lose the gas it took you to get to that speed. Driving "stop and go" makes you use a lot more gas than coasting to places.
  
  

As you can see you can do much better with very little money by driving smarter, rather than putting one gallon of gas in at a time. People tend to think they drive a little better on vapors, and whether or not it may be true in some cars, it is perhaps a better idea to take your one to five gallons of gas, and spend it more wisely than miserly.

If you are in a cold climate, some folks suggest you keep your tank filled. A filled tank does not get as much condensation, which can travel through your gas line and freeze. This can result in a non-starting car or a ruptured gas line. If you insist on the gallon-at-a-time method, make sure you put dry gas in your tank. Dry gas is a gasoline additive that absorbs water, and you'll only need it during the times when the temperatures get below freezing.

Switching to motorcycles, I always leave the tank filled with StaBil and dry gas over the winter. StaBil will keep the gas from going bad and the dry gas will keep condensation from rusting your tank from the inside out. When I used to ride classic bikes like the venerable Honda CB350, when I'd pick up a parts bike the tank would almost always be rusted out, the petcock was gummed up, and the carburetor had gummed-up jets and the floats were squashed from water getting trapped.

There is another reason why this is a bad idea. The fuel pump in most production cars is electric, using a high-speed motor driven impeller to create high pressure in the fuel line. The fuel pump dissipates a lot of heat performing this task, which is typically absorbed by the surrounding gasoline bath. If you're running on empty all the time, over time your pump will grow tired of overheating and wear out.