The service life of a spherical plain bearing operated under mixed or dry friction conditions is determined by the in crease in bearing clearance or bearing friction caused by progressive wear of the sliding surfaces, plastic deformation of the sliding material or fatigue of the sliding surface. Depending on the application, the permissible wear or permissible increase infriction will be different. This means that under the same operating conditions the service life which can be obtained in practice will be different. 

The service life of a spherical plain bearing is the number of oscillating movements, or the number of operating hours, which the bearing will service before a defined increase in bearing clearance or a defined increase in friction is reached. 

The effective service life is that life which will be attained by a given spherical plain bearing under actual operating conditions. It is determined by the magnitude and type of load, but also by several other factors, such as contamination, corrosion, high-frequency load and movement cycles, shock. Some of these factors are impossible to determine or can only be determined with difficulty.