As the number of components in an electronic appliance increases, the number of factors influencing its service life also grows. In some cases, an appliance’s service life is considered equivalent to the Mean Time Between Failures (MTBF) of its electronic components.

However, for a fan, its service life is typically determined by the longevity of its mechanical components rather than its electronic ones. Specifically, the bearing in the motor that drives the blade is the most crucial factor. Although various types of bearings exist, ball bearings are commonly used in cooling fans due to their high reliability.

Ball bearings have two types of life: fatigue life and grease life. Unlike industrial motors, the load on fan bearings is relatively light, so fatigue life is rarely a concern. Consequently, the grease life of the ball bearings becomes the most significant factor affecting the fan’s overall service life.