When can the maintenance be a source of profit?

When the company maintains and repairs its equipment and plant carefully in regular basis, the investment in capital equipment will be reduced.   

Example: If you maintain and repair equipment carefully as per maintenance schedule, it may last say for “six years”. If you do not maintain properly, it may last for “three years “.Then you have to buy the same equipment again, your investment will go up thereby reduce your profit margin or reduce return on investment.