ABR or block replacement policies are often used for many components in a plant. These policies allow the creation of long-term maintenance schedules. From these schedules it is clear that, at a certain date in the (near) future, unit X will be shut down and will be serviced by team Y. Production managers can then plan activities based on this information, such as adjusting their production plans, allocating maintenance crews, and so on. If ABR is non-ideal, the corrective actions will disturb the smoothness of the maintenance plans and reduce the possibilities
for grouping maintenance activities, because (the potential for) grouping can no longer be engineered and planned long in advance but is dependent upon the (unpredictable) timing of the failures.