do you consider doing major repairs(transmission, engine etc.) with your cars?
the drawback of cost per mile is that any major repair will set you back. This certainly isn’t a flawless, one-size-fits-all equation. But I suppose if you can get your use out of a car it’s still money well spent.
Yes, of course. That's sort of the purpose. So I can have a simple easy gauge of what has been done, what is needed, keeping track of costs, parts, labor prices, which shop did which repairs and when, mileage for various intervals like oil changes and transmission and differential changes, etc. Big ticket items absolutely go on the trackers.
Gas, never. It's a sunk cost and so trivial between different vehicles. I just reset the trip odometer every fillup, and do a quick division to see that I'm getting ballpark what I expect mainly to ensure I don't have a hidden fuel leak or problem. I don't put insurance there, b/c that's also a sunk cost and I know they are all about the same with my excellent rates.
I do "look back" and do "year in review" on vehicles to see if they are/were a good investment for their designated purposes. So far, one in my fleet is more expensive than I had anticipated, but I'll keep it and the longer I own it the cheaper it gets.
It's not flawless. There are intangibles such as pleasure, intangibles such as a utility vehicle keeping miles off a more valuable vehicle for errands, etc.