Total product quality is multidimensional and includes customer acceptance as well as the usual quantitative elements for conformance, performance and reliability. Also included are broad ranges of operational expectations that are specific to the particular product. Thus to assess overall quality requires analysis of a multi-attribute vector of quality measures, some of which are subjective but cannot be ignored in making quality-related decisions. Warranty costs reflect the overall effect of these elements and can serve as an overall measure for making economic decisions. In this paper, we will summarize warranty cost models and describe two warranty planning problems that are important in engineering economic decision making.