In this talk, we shall present a few industrial cases in which reliability assessments are needed for making decisions relating to fleet management, product design and replacement strategies. These cases highlight the use of engineering knowledge with statistical modeling for better decision making. In particular, we look into approaches in analyzing large fleets of repairable systems, how to improve product design risk and mitigate warranty costs. These examples motivate some interesting theoretical development of new ideas in the analysis of repairable systems and the planning of reliability testing.