Not every asset deserves the same maintenance attention, and criticality analysis is the exercise that decides which do. A backup pump with a spare on the shelf and no downstream impact ranks low. A single AS/RS crane with no manual fallback, feeding every pick in the building, ranks as high as it gets — regardless of how often it actually fails.
The output is usually a simple tier system (critical / important / standard) that then drives everything else: which assets get condition monitoring, which get quarterly versus annual inspection, and which are fine to run reactively.