I worked up a similar spreadsheet to be able to accurately describe the cost of driving our cars & trucks, for a variety of reasons.
While most of the values are guesses, I've tried to be close by checking records or figuring out how much things cost today. Specific things on the list are similar to your list:
- Fuel costs (mpg)
- Oil change cost (varies some by vehicle; my truck takes 14 quarts)
- Tires (cost for new set vs miles)
- Estimated repairs over the next 10,000mi (based on guesses as to what it may need for the age of the vehicle, etc)
- Estimated depreciation for 10,000mi (not time - I'll have the car during that time regardless so the only issue is how much does putting mileage on the vehicle cost)
- Other required gear cost (motorcycle gloves wear out pretty predictably, and helmets need to be replaced more due to use than time, though time has some effect as well)
It's definitely a useful exercise, even if it's only ballpark. I first did this when a beancounter at an old job balked at giving me the IRS rate for mileage reimbursement, instead trying to arbitrarily choose a value based on what he thought operating a car cost. The depreciation really drives up the cost in many cases.
For what it's worth, when diesel was substantially cheaper out here (California has high fuel costs, and quite often diesel is more expensive than super), my truck with ~14mpg was cheaper to drive by my estimates than our 30mpg compact (its low mpg being partially offset by cheaper fuel, but primarily the lower cost was because the truck is 20 years old and has higher miles already and isn't going to depreciate much!).
Having this sort of information is useful when it's time to do things like rent a truck to move someone (showing that a rental may actually be cheaper than driving), decide if it's cheaper to fly or drive (around here, it's typically a wash for me to fly vs drive for one person - and if you're only flying 400 miles, it's probably not much different time-wise either factoring in parking (costs $ too) time and sitting around waiting for a plane and pickup).
I can see doing this for a tractor being good in that it's good to know that "every hour I'm using isn't free, make it worth it".
Don't forget the cost of tires - figure new cost, divided by life span; it's probably a decent chunk of a dollar per hour.