New cars tend to decrease in value by 25 to 40 percent in the first two years [source: Fuller]. Buying a car that's a year or two old means somebody else paid that 40 percent when they turned it in, or sold it to you, without a substantial drop in quality. That change in price will also be reflected in your warranty and insurance prices -- another thing the previous owner paid on your behalf.
As we all know, the best way to save on month-to-month car expenses is by watching your mileage. But it doesn't have to be a statistical nightmare. Just think about the basics: If you drive 80,000 miles (129,000 kilometers) over an average of five years, you could be buying 2,000 fewer gallons (7,600 liters) of gas simply by choosing a 25 mpg (11 km/L) car over a 15 mpg (6 km/L) model [source: U.S. Environmental Protection Agency]. That's a lot of gas saved!
Did you know that just changing your air filter could raise your mileage by as much as 7 percent [source: Roth]? Or that for every 2 pounds per square inch (psi) -- 14 kilopascals -- that your tires are running low, your mileage goes down by 1 percent? Most cars are 5 to 10 psi (35 to 70 kilopascals) under their manufacturer's requirement, and just airing them up, at negligible cost, means an improvement of around 5 percent [source: Parkhurst and Zatz].
All these little things add up to save you money -- plus, keeping your car in top condition means many more years until you'll need to buy a new one!