Tests on the Model 3 motor revealed minimal wear at 1 million miles, and the motor was still running strong. Elon Musk has said they do not do a “refresh” like other car companies: “Get this question a lot, so need to clarify that there’s no such thing as a Tesla ‘refresh’. Other car companies do this every ~3 years, but Tesla constantly upgrades vehicle hardware every week.” Elon Musk
In addition to no gasoline expense, the brakes are designed to last the life of the car, no oil changes, no tune ups, no complicated fuel and exhaust sensors to go bad, no exahust, no muffler, no catalytic converters, the list could go on, and what gasoline engine can go 1 million miles? The battery packs so far have proven to last a very long time. A Tesla Model S taxi has over 250,000 miles on it and the battery is at 93% capacity, only a 7% degredation. There are other reports of a Model S getting over 400,000 miles on it. These cars have no major maintenance costs and no expensive engine repairs.
These cars are also constantly being perfected with over the air (OTA) software and firmware updates.