A relationship exists between the amount of preventive maintenance which has been performed and the amount of corrective maintenance which will be required. An increases in preventive maintenance can be expected to reduce the frequency with which the need for corrective maintenance arises.

a. A component which is not replaced or repaired for preventive reasons when it eventually malfunctions and damage other components of the asset.

b. The corrective maintenance cannot be planned and scheduled as systematically and efficiently as preventive maintenance .

Preventive maintenance is a planned activity and analyst knows when it will take place, how much time it will require and what resources are required for its implementation.

For corrective maintenance the analyst would have to know the number of future. Breakdown the point in time when they will occur and the nature of malfunctions. All these information predictions can be based on the past maintenance records of the assets involved.