Abstract: In order to oversee and plan, at overall shop level, the execution of maintenance work on several installations (1), each having monitoring equipment (3) which monitors the intervals at which maintenance should be carried out on the installations, it is proposed that the outputs (A.sub.3) from the monitoring equipment (3) be fed to a processing unit (27) which produces maintenance status reports (53) for the whole shop. Registers, which store certain maintenance intervals, are reset only upon recognition of maintenance personnel at the site of the installation by manual input and recognition of the condition at the processing unit by a remote input.