My point is that it is not exact science. You cannot get exact parameters to single $.
Sure, but you can still run numbers and try to be educated. Nothing worse than someone (here or in real life) realizing that their new purchase has some routine high cost item that they didn't know about.
Yes, I still have fleet of cars. One thing I never did, or wanted to do is to save as much as possible. When you start to do that, you lose something much more important: employee. And that costs much more than saving absolutely every penny on vehicle upkeep.
Ah, I see. You were ok with perhaps a higher vehicle TCO in order to drive down employee turnover costs, thus leading to a better bottom line. Makes sense.
I'm an employee of one, pretty hard for me to fire myself.

Although somedays I sure wish I could... [I try to view myself as being in business, that way I try to look at my decisions impartially. How will it affect my bottom line? in an attempt to avoid poor decision making.]