This document discusses categories of quality costs including conformance costs (prevention and appraisal) and non-conformance costs (internal and external failure). Prevention costs aim to avoid defects through activities like quality planning, supplier evaluation, and calibration. Appraisal costs detect defects through inspection and testing. Internal failure costs occur when defects are found before delivery, while external failure costs happen when customers find defects. The document advocates reducing non-conformance costs through prevention rather than increasing prevention costs. Total quality costs can be 25-35% of sales, but many costs are hidden. Implementing total quality management can significantly reduce costs over time.