I know this seems crazy, but I also count the service/maintenance of the car as part of the purchase. I look at the entire picture, not just my monthly note on the car. What the maintenance costs are and how often, etc, etc.
There should be no surprises because if you do your homework you should know what it costs and takes to maintain your new vehicle. There is no other way to look at it and make an informed decision. There should be no "YIKES" or surprises