A measure of functional degradation or its surrogate is more informative than attribute data such as failure time when improving designs or developing meaningful tests. This paper delineates the advantages and disadvantages of using degradation data, and the situations under which one should or should not use degradation analysis. A comparison has been done between degradation testing, testing to failure, and bogey testing. The steps necessary to apply degradation analysis techniques to product design have been described: determine scope of the project, plan degradation test, collect data, analyze data, and document results. A case study has been used to demonstrate the whole process of degradation analysis techniques.