Legal regulations
Almost all countries in the world have regulations on the use of units, measures, weights and measuring instruments. These stem from the governmental care for fair trade, safety, health and environment.

Use of units
The European Union adopted a directive on Units of measurement in 1979 (80/181/EEG). In the Netherlands this directive has been implemented in the IJkwet (Metrology Law) and the Eenhedenbesluit 1981 (Decree on Units). This is based on the 7 base units: metre, kilogram, second, ampère, kelvin, mole and candela. In principle, it prohibits the use of non-acknowledged units.

Requirements on measuring instruments
Measures, weights and measuring instruments must be fit for purpose. The government puts specific requirements when these items are used for measurements for trade purposes, for official measurements (for example by police or customs) an more and more in case of measurements and determinations in the framework of safety, health and environmental protection. In the Netherlands most of these requirements have been laid down in the IJkwet (Metrology Law). On the European level and globally the regulations are ever more harmonized. Often they include (also called pattern approval) an initial verifications when instruments are taken into use. See further terms in legal metrology and organizations in metrology.

Market surveillance
Government keeps an eye on the use and status of measuring instruments used for the purposes mentioned above. In the European Union the national states are even obliged to do so. Many countries have introduced mandatory reverifications. In the Netherlands this is not the case for most categories of measuring instruments. Market surveillance is confined to periodical inspections that are performed by Verispect B.V. in commission of the Ministry of Economic Affairs.