This guide explores methods for assessing measurement errors in real-world operating conditions. It includes practical examples of how to evaluate the accuracy of measuring instruments and provides solutions to common problems in measurement error estimation. Designed in accordance with the curricula for courses such as "Metrology, Standardization, and Certification" and "Metrology and Certification," these materials are intended for second to fifth-year students specializing in programs 200503, 220501, and 221400. The methodological instructions are useful for studying these disciplines, as well as for completing control assignments, coursework, and final projects.