eli5: Why do cars have limited miles?

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If you have a car and you continue to fix it every time a problem occurs, why can’t you keep the car and drive it forever as-long as you have to money to fix it if something goes wrong?

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20 Answers

Anonymous 0 Comments

You can do that, but the car gets to the point that you no longer like it enough to keep spending money fixing it.

Anonymous 0 Comments

There are Model T Fords still running. Some vehicles even older.

Parts can also be a problem as no demand for them and not being made anymore.

Anonymous 0 Comments

Technically you could, just keep replacing parts indefinitely, on exotic cars worth a lot of money it might be an option, but as the commentor said at what cost. How much is a new motor or gearbox on a 20 yr old car

Anonymous 0 Comments

It’s not a hard limit, it’s more like an estimate average of how likely it is to last before it becomes more expensive than it’s worth to fix it.

Anonymous 0 Comments

Car of Theseus!

Main problem is money, as time goes on, the things that wear out (mechanically wear or chemical fatigue) become more complicated (and thus expensive) to repair than you’d want to spend. Second reason is part availability, companies stop producing the parts you need and you can’t find them in junkyards; though this comes back to money; if you’re willing to spend a zillion dollars to have a bespoke wiring harness built to replace the one that fried when the insulation failed, or the plastic on the headlight bracket that cracked due to heat cycling, or the weird spacer keeping the seat on its tracks… sure. It’s just money.

But for a sufficiently “appealing” car (read: $$$$) people do all these things regularly. Wealthy people.

Anonymous 0 Comments

In theory if you had enough money and the desire to, you could just fix and replace parts as they wear out. As long as you know how to make those parts or have enough time and resources to pay someone to make those parts, it is possible to keep a car running nearly indefinitely.

In the real world, though, there are probably things that prevent this. It becomes VERY expensive and inconvenient. Making one-off parts takes a long time so the owner must be prepared to hold lots of spares or wait a long time with an unusable vehicle while things are repaired.

Modern high volume production makes newer cars very much greater in value for money in terms of technology, reliability and comfort as well as functionality (not to mention safety). Few people would pay lots of money to keep a car running that is inconvenient, unreliable, uncomfortable and difficult to use.

Finally there are laws and regulations – the modern ones on safety and emissions might make it hard to register a vehicle for use on public roads. In which case, the vehicle might be drivable but just not legally on public roads – limiting its usefulness.

Anonymous 0 Comments

Eventually the value of the car is less then the money needed to fix the car and hence it’s time for a replacement. Theoretically you could drive a car forever just constantly repairing and replacing as necessary but eventually you will be riding a new car essentially with nearly every component of the car being replaced

Anonymous 0 Comments

Two reasons

Economical: there can be hurdles to keep fixing a car. As it ages and wears, the failures of parts and repair needed can become expensive. Parts get discontinued by the mfr. aftermarket companies can’t justify reproducing all but the most common service parts for cars. Or a particular repair, while possible, could be so labor intensive that the cost to fix the car is just so much greater than the utility value of car itself. Technically the car could be fixed but nobody is willing to put the time and money in required to do it, compared to the other options, I.e junk the car and buy another one.

Environmental: cars are generally made of materials that corrode in humid environments: steel, iron, aluminum alloys. If they are used in places where roads are salted in the winter the process is accelerated. No car is immune to corrosion, it can only be slowed down by paint, rust protection coatings etc. eventuality the structure of the car will become compromised and unsafe. This is a big limitation of vehicle life in some locations, while some ideal climates (dry with no winter snow!) corrosion is hardly a concern at all.

Anonymous 0 Comments

You can run it forever, but would you spend $8k to replace an engine on a 20-30 years old car after it wears out? parts do not last forever, eventually everything needs to be replace.

Anonymous 0 Comments

You absolutely can. My car has 418,000 miles on it, and my truck has 310,000. Many people have higher mileage than me, too.

It’s just that most people want something newer, they get tired of their car, the car’s value is less than what it will take to fix the car, or they decide payments are easier than an up-front repair bill.

Sometimes the parts can be difficult or impossible to find, depending on the car.