This article examines the differences in the lifetime of mud pumps, which are part of the equipment on (ultra) deep-water drillships, depending on the strategy of maintenance. The authors conducted research on mud pumps to create an efficient diagnostic tool to help pumps operators on daily maintenance routines. We have created drilling process diagrams, one pertaining to the operation of mud pumps for which maintenance is carried out without technical supervision, the other including diagnostic maintenance. The diagrams show differences pump failure frequency.