Plastic parts undergo both chemical and physical aging during their use. The prudent plastic part manufacturer seeks to demonstrate the useful life of their product in order to determine an appropriate warranty period. Of course, running laboratory tests that last several years to gain life time expectancy data is not useful. Therefore there is a need to develop accelerated laboratory testing methods that reliably can predict the useful life of plastic parts. In general, accelerated aging is a well-established science and has been used successfully to predict performance in a wide variety of plastics and aging conditions. There are conditions and situations that can lead to erroneous results, but these are generally known. This underlines the importance of a Materials Science evaluation of the polymer and aging conditions, coupled with a knowledge of the chemistry of polymer degradation and its associated kinetics. When this type of analysis is done prior to developing the experimental protocol, the results of laboratory accelerated aging studies are reliable.