Under a given load, the number of revolutions or hours a bearing operates before pitting occurs is referred to as bearing life.

The life of a rolling bearing is defined by revolutions (or operating hours at a specific rotational speed): within this life span, the bearing should exhibit initial fatigue damage (spalling or spalling defects) on any bearing ring or rolling element. However, both laboratory testing and practical application clearly show that bearings with identical appearance under identical operating conditions can exhibit significantly different actual lifetimes. Additionally, several distinct definitions of bearing “life” exist, one being the so-called “working life.” This denotes the actual service duration a bearing can achieve before failure, where damage typically results not from fatigue but from wear, corrosion, seal failure, or similar causes.

To establish a standard for bearing life, it is linked to reliability.

Due to variations in manufacturing precision and material uniformity, even bearings of identical material and dimensions from the same batch will exhibit differing lifespans under identical operating conditions. If the statistical life is set as 1 unit, the longest relative life reaches 4 units, while the shortest is 0.1-0.2 units, resulting in a ratio of 20-40 times between the longest and shortest lifespans. The number of revolutions or operating hours experienced by 90% of bearings without pitting is termed the bearing rated life.