In a method for determining the life expectancy of machine components (2) during operation, characteristic data are established in order to determine the life expectancy for the relevant machine component (2), loads acting on the machine part (2) during operation are determined by means of a sensor device (10), characteristic values that are characteristic for the loads acting on the machine component (2) are determined, and the life expectancy is determined based on the characteristic values and on the characteristic data for the machine component (2).