What requirement must be followed when performing a calibration according to customer requests?

When performing a calibration according to customer requests, the most appropriate requirement is to always record the measurements made. This practice is critical for several reasons.

Firstly, recording all measurements provides a complete and traceable record of the calibration process. This documentation can be essential for quality control and assurance, as it enables both the technician and the customer to review the calibrations conducted, understand the conditions under which they were performed, and verify compliance with specific standards.

Additionally, thorough record-keeping can help in identifying trends or issues over time, which is invaluable for maintaining the reliability and accuracy of equipment. It ensures that any variances or discrepancies are documented and can be addressed, fostering a collaborative understanding between the technician and the customer regarding the equipment's performance and calibration history. This practice ultimately supports a more transparent and accountable calibration process.

In contrast, simply recording data when asked, only recording final results, or ignoring differences found during calibration do not support best practices in calibration. These approaches may lead to incomplete data sets, lack of accountability, or missed opportunities for corrective actions, all of which compromise the effectiveness and reliability of the calibration process.