Depreciation
The value a car loses between purchase and resale — invisible day to day, yet often one of the largest costs of owning a new car.
Nobody writes a monthly check for depreciation, which is exactly why it hides in plain sight as one of the largest costs of running a new car. It is simply the difference between what you pay and what the car fetches when you sell — realized only at the end, but accruing from the moment of first registration, usually steepest in the first years and flattening thereafter.
Rates vary between models, and that variance can matter more than a discount on the list price. Brand reputation, reliability record, supply of the model on the used market, fuel type sentiment, and even option choices can move it; incentives that discount new prices can push used values down in sympathy. For electric cars, battery health perception and the pace of technical progress add their own pressure in both directions.
In a TCO comparison, depreciation is often a heavyweight line item, and the projected end value it hinges on is the residual value — see that entry for how the projection is made and used.