As a refrigerator pulls the heat out of the storage cavity, it vents it slowly and evenly into the kitchen through condenser coils. A buildup of dust around these coils acts like insulation and keeps the coils from releasing heat, which shortens the life of the machine.
These coils, which look like bedsprings, are usually at the bottom of the refrigerator, under the grill, although they also may be located at the top or in the back of the refrigerator. Twice a year, or more if you live in a particularly dusty climate, clean the coils, either by vacuuming with the crevice attachment or by using a refrigerator coil brush, a long, thin brush capable of getting into tight areas, available at home centers and hardware stores. Be sure to shut off the power at the circuit breaker or fuse box beforehand.
By cleaning your refrigerator coils periodically, you will ultimately extend the life of your refrigerator.