Successful configurators are based on high quality: User expectation (requirements), product offering (configurability), technical correctness (feasibility), and producibility must align. Quality affects all aspects of product configuration: Knowledge base (modeling), user interface, data sources, and configuration result. Error prevention (instead of only correction) leads to cost reduction. This chapter sheds light on typical problems related to quality, presents strategies to ensure high quality, drawing from good software development practices, and describes possible causes for configuration project failures.