The life of a bearing is defined by the number of rotations (or hours of work at a given speed). Bearings within this life should suffer from initial fatigue damage (spalling or defect) on any bearing ring or rolling element. However, no matter in laboratory test or in actual use, it is obvious that the actual life of bearings with the same appearance under the same working conditions is quite different. In addition, there are several different definitions of bearing "life", one of which is the so-called "working life", which means that the actual life of a bearing before damage is caused by wear, damage is usually not caused by fatigue, but by wear, corrosion, seal damage and other reasons.