What the car costs to keep

The cheapest car to buy is often not the cheapest car to own, and the most expensive month of ownership is usually the one where something breaks. These tools price the decision you make after the car is already in the driveway: keep it, replace it, or fix it one more time.

All three work in the same unit — cost per mile — because that is the only way to compare a repair bill against a car payment, or a higher purchase price against a lower running cost. Depreciation, insurance, maintenance and tires are inputs here, not omissions.