The regulations for the qualification of clean areas in manufacturing of sterile medicinal products are defined in the current Annex 1 of the EU GMP guidelines. A decisive part of this qualification process includes the classification according to EN ISO 14644 to ensure that measurements are carried out in compliance with the standard. Special attention is paid to the measures defined in the contamination control strategy. In order to meet the Annex 1 requirements, the measurement intervals are optimized by applying risk-based approaches. Thereby critical parameters receive particular attention, while monitoring frequencies are reduced for less critical areas. This approach enables a targeted reduction in effort without compromising the quality of the measurement data. In addition, shorter test intervals for requalification and a clear distinction between qualification and monitoring must be considered. From these guidelines, relevant actions for essential measurings can be recommended, which are intended to serve as support for GMP-compliant and efficient cleanroom measurement.