As little as possible if I can help it
 

As little as possible and no new car if at all possible. But it all depends on individual's comfort zone and circumstances. So everyone is different and there is no over-spent or under-spent so to speak.

My target is to get it down to $0.08 per mile for all my driving needs. That includes insurance ( 3rd party only ), maintenance, consumerable, DMV licence and fuel costs. I am under my target from 1/1/10 to now. We do about 35K per year combined.

BTW: I discounted the car depreciation as the initial investments were dirt cheap. I would never, ever, spend more than $3K on repairs on any of the cars. There are a lot of good MBZ diesel to be had for $3k. Why sink money into a losing proposition?

Including tools and repairs?

Over how many years do you depreciate the purchase price?

How does any of that make a difference to anything here?

Everything. I spend about $0.15 per mile for fuel. I drive about 50k miles per year so; $0.15 x 50,000 = $7500 per year for maintenance, repairs, etc. The current IRS rate is $0.50 per mile, so I'm happy as long as I don't exceed that cost.

I only paid about $8000 for the car 350,000 miles and 10 years ago, so the original purchase price us negligible on a per mile basis. The car has paid for itself several times over.

Used cars cheap as possible consistant with reliability at our needed level. Less than that you should have a back up vehicle. I tend to keep an eye open for low milage cars in good condition.Dare I say for a reasonable price as well. I may buy a car a year before it sees service with us on occasion.

I really try to stay away from models for daily drivers that have a pronounced tendency to have issues. Certain current cars I would not want if someone gave them to me.

We dump our daily drivers as soon as it starts to look expensive or time consuming to keep the reliability in that car. Cost per mile I do not bother to track as we are stuck with that anyways. Other than that I try to stay with daily drivers that on average depreciate less than a thousand dollars a year each.

Some years ago I was finished with costly cars for daily transportation. I just felt it was a total waste and occasionally telegraphed the wrong image as well.

To keep two daily drivers on the road for my wife and myself probably costs an average of eight hundred a month including fuel, self done maintenance, insurance, registrations and depreciations. This is just a guess but seems about right to me. We pay about 4.50 an american gallon for fuel as well remember. So this may drive the cost of ownership a little higher than an american experiences in simular circumstances.

In my youth one car per family was the average if the children were young. Today two cars seem an absolute neccesity. Even if ancient and semi retired as we are. This semi retirement is a killer for us as we are always still so busy. As I sit here typing I almost feel guilty about what I should be doing instead. I am learning to live with the guilt I suppose as well.

Although it can wait as I will never get caught up anyways even if I tried. If there is light at the end of the tunnel I will have to shovel out the tunnel first.

I bought a very good condition 85 W123 300d, 175K no rust. It bacame the default daily driver the day it arrived due to my main car blowing a brake line. Came to about 4,000 after taxes and registration. I immediatly started driving it and have put 1000 miles on it already with no big problems. Due to its condition, I plan to drive until snow and salt begin then use it again one the weather improves. For me anyway, anything under $10K would be in the daily driver elegible class. My 58 on the other hand doesn't even go out in the rain.