In any system the efficiency of an item (such as machine, man, part) deteriorates with time. In such cases, either it should be replaced with new item or it should be under maintenance to restore the efficiency of whole system.
Replacement and maintenance models are concerned with the problem of replacement or maintenance of machines, individuals, capital assets, etc. due to their deteriorating efficiency, failure, or breakdown.
Types of failure
1. Gradual failure
2. Sudden failure
This material is intended as a summary. Use your textbook for detail explanation.
Any bug, improvement, feedback then
