StormCloud Wrote:
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> I'm currently driving a 2003 Dodge Caravan that
> gets about 20 mpg. We do oil changes every
> whatever miles, but usually I do them on a mystery
> shop so it's reimbursed. Tires? Other
> maintenance? Eventual replacement? How does one
> calculate those?
Just because an expense is reimbursed doesn't mean that it's not incurred. I always factor in expenses regardless of whether I find shops to offset them, because sometimes I may not get that shop. I estimate oil change expenses at $0.006/mile ($25/4000).
My primary vehicle is still under 20,000 miles, so I don't calculate wear & tear, as everything aside from maintenance is still under warranty. I still tack on $0.02/mile for fluid changes and other scheduled maintenance though.
Tires will vary per vehicle, but the way I calculate them is the price for a set of 4 divided by expected life. A set of 4 decent tires for my vehicle is roughly $900, and should last approximately 50,000 miles. So, I factor in $0.018/mile for tires.
As for vehicle replacement/depreciation costs, it's a very fuzzy science. There are so many variables such as vehicle condition to take into consideration, coupled with the fact that you're essentially trying to predict what the vehicle resale market will be at some point in the future. One thing that I may try to do in the coming year is mark the book value of my vehicle in January and the book value of my vehicle in December. I would then look up the book value of my vehicle in December, but subtract off the mileage used for shops and see the difference. I could then divide that difference by the amount of shopping miles to get a per-mile accelerated depreciation cost and add that to next year's calculations, so long as I expect to use the same amount of miles in that year.