Stationary applications of Solid Oxide Fuel Cell systems require operating times of 40,000 to 80,000 h for market introduction. Therefore, extended lifetime tests are essential for learning about the long-term behavior and various degradation mechanisms and to foster ideas about accelerated stack testing. The Forschungszentrum Julich has been gradually extending the testing time, resulting in successful short-stack operating times of between 20,000 and 40,000 h. This work highlights the results of these long-term tests and compares the observations for different material combinations, operating temperatures of 700 and 800 degrees C, including different fuel utilizations and gas compositions. An increase of temperature from 700 to 800 degrees C leads to an acceleration of the degradation rate by a factor of 1.5-2. Meanwhile, an increase in fuel utilization from 40 to 80% did not result in increased degradation. The same was found for higher current densities of up to 1 Acm(-2). (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.