If one could get the right mix of preventive maintenance (PM) and corrective maintenance (CM), things might not be so bad. If CM could be reduced to zero, that would be grand, but that is not going to happen. Amid the propositions of RCM, TPM, RCA, the Pareto rule, best laid plans, etc., one still must contend with randomness. When our programs result in high levels of performance, the limiting factor is often randomness. Using the concept of randomness in analyzing equipment failure events is helpful in establishing the realistic limiting factors in PM and CM program development and management.
Before getting enthused about understanding the technical milieu of equipment failure modes and causes, failure intervals and maintenance task development in recovering a dysfunctional maintenance program, first look for an opportunity of a large reward for a small resource expenditure.
One large reward, for example, could be a 50% reduction in corrective maintenance resulting from a program developed and implemented in-house (small resource expenditure). That 50% number is not unrealistic.