Life cycles of modern protection IEDs are becoming shorter and shorter. Additionally, the time spans between firmware updates for these devices are decreasing. Therefore, the needs for qualified testing strategies are increasing. The utility needs to verify e.g. the functional requirements, the quality of the new firmware, the correctness of commissioning, the parameter settings and more. This paper focuses on the one hand on the life cycle of a protection device from a utility point of view. The paper classifies the different phases of this life cycle and shows the requirements for testing in different phases. The aspects of testing from first prequalification work to the periodical maintenance tests are discussed. Due to the new approach the testing quality could be increased while the testing time is decreased at the same time. The idea of this method is taken from software development, where a regression test is used to check a new software version. This method requires written definitions describing the various types of tests the IED has to undergo during its life cycle. Due to the high quality of the documentation the utility has a good tool to keep the knowledge in the company.