Back in the early days of American JIT manufacturing, a colleague asked me what would be the proper number of inventory turns for car parts going into an auto assembly plant we were overhauling. Back then magic numbers were, for me at least, much more important than they are now.
Maintenance performance upgrades are becoming common these days. The improvements may come from several directions: Reliability is becoming better understood and respected. Overall Equipment Effectiveness (OEE) is driving some of the efforts by raising expectations of equipment performance.