Under The Car
The battery is another thing that requires a regular service, not too much, but important. You need to make sure the battery fluid is up to the full line and that the terminals are clean and free of snow. Also the top of the battery needs to be clean to prevent current leakage between the terminals. This should be done every 7,500 miles.
There aren't too many things under the car that require maintenance, but those few things there are will add life and comfort to your car. The most important of these are your tires. Your car came with good tires, but they are a compromise between cost and quality. When it comes time to replace them you'll probably upgrade the quality of your tires and not pay too much attention to the cost. The best way to get the most out of your tires is by having them rotated and balanced on a regular basis, every 7,500 miles. This will ensure that they wear evenly and last as long as possible. Balancing is important because a properly balanced tire reduces the stress and strain on shocks, struts, and steering parts in general. Keeping the tire pressures set to specification will also go a long way in extending tire life and fuel economy.
Replacing the differential fluid is something that is most often over looked. While differentials are pretty robust and solid, a regular fluid change will help them stay that way for the life of the car. If your car is four or all wheel drive, change the transfer case fluid as well.
By having the brakes serviced at 15,000 mile intervals you'll insure top performance from them. Cleaning the brake pads and rotors will ensure that they are quiet, wear evenly and working properly.