Theoretical modeling continues to play a larger role in noise and vibration engineering; however, until products are perfectly made, there will be a need to evaluate their end of the production line performance. Manufacturing production of a wide range of items has classically involved some amount of subjective and/or evolved objective quality testing along, or at the end of the production line. This testing can have goals of determining product safety, durability, functionality, and/or the vibration/sound quality. A vibration-based measurement approach is frequently used for many of those goals. Often, many modern products utilize some combination of electric motors, internal combustion engines, and power transmission rotational components. The end-of-line testing for many of these rotational components is after many years now heavily refined in the measurement and analysis methods, and the separation of good, bad and marginally bad samples may not always be challenging. It is frequently the non-standard types of products or unique operating conditions, either as subcomponents or assemblies, which may provide unique challenges to the typical measurement and analysis methods. Additionally, depending on how new the end-of-line evaluation process is to a manufacturing company, then the process may be aided with additional steps beyond typical site survey and final pass/fail system integration. These additional steps may include noise and vibration troubleshooting for source localization, informal or formal listening studies to rank good, bad and marginal samples, and the investigation of non-standard analysis methods. The goal is to always be able to reach performance standards at the end of the production line. Sometimes, the methods used for evaluation at the end of production may also then be refined and extended into lifelong condition monitoring of the product in a final application.