Preventative maintenance will be referred to PM from here on in. PM should be considered parts with a certain life span before needing replaced. If you are not planning to replace or rebuild an item during the equipment's life, it costs you zero because it will be accounted for. Listed below are parts I considered, but this list can be expanded or condensed to your personal preference. This issue is a little tricky, because you are adding a variable or unknown into the formula unless your records are very extensive. What you have to do is put a mileage expectancy on an item and a cost. Let's give you an example. You are going to expense out an alternator. The alternator you have is new and cost $357.00. You estimate it will last 400,000 miles before it needs replaced. Divide the price of the alternator, $357.00 by the miles 400,000, giving you a PM cost for the alternator of.00089 per mile. Another example is sooner or later you will have to do a rebuild on your engine. Let's say a rebuild will cost you $6700.00 and you scheduled your rebuilds at 700,000 miles. Take the cost of rebuilding your engine $6,700.00 and divide by the 700,000 miles. This gives you a cost of.00957 per mile for engine wear. This issue becomes impossible if you purchase a used unit without maintenance records. I personally wouldn't purchase a vehicle without them.
This is the formula for calculating rebuild costs per mile.
COST OF REBUILD + MILES ON SCHEDULED REBUILD = REBUILD COSTS PER MILE
This is the formula for calculating per mile cost.
COST OF PART + ESTIMATED OR KNOWN MILEAGE LIFE = COST PER MILE FOR PM OF THAT PART.
