The current IRS deduction is fifty three and half cents per mile. This seems reasonable to me overall.
It can be very difficult if not impossible to predict what your cost is going to be on a given vehicle, because you have no way of knowing for sure ahead of time what the reliability and therefore the repair costs are going to be for that one car or truck.
It's good to be flexible in life and know when it's time to cry uncle, and just move on to something else. Sometimes the expenses just are not worth it, other times, they are.
I like my trucks a lot, and really like being able to use my trailers for the things I enjoy in life ( traveling with the funfinder in tow, or using the horse trailer for taking horses to shows ) so the cost has to be looked at as simply part of the cost of my life activities.
The alternative is I suppose to sit at home and be bored.