This paper proposes a new methodology for optimizing maintenance and monitoring performance. The performance of the monitoring device is modelled classically by receiver operating characteristic (ROC) curves. From a practical point of view, this approach leads to a very simple optimization scheme in which the optimal monitoring technology or structure can be chosen among a finite set of possible ones, on the basis of their impact on the maintenance performance and their own cost. At the same time, the maintenance parameters are optimally tuned to adapt to the current monitoring quality level. Compared with previous work on the subject, this work allows the assessment of a more realistic integration between maintenance or reliability concerns and monitoring ones, owing to comprehensive reliability/maintenance/monitoring performance modelling.