How do cars die at old age?

So how exactly do cars fall apart to the point where you have to buy a new one. I have an old honda and i just don't see it happening to my car at any point in the future. Why would i NEED to buy a new car? What will eventually happen to mine?

They don't normally fall apart.

What happens is they eventually get to the point where individual parts are wearing out too often to make it financially feasible to replace. It becomes cheaper to buy a newer car than repair the one your have.

Dodge charger left abandoned to rot.

There are car owners with 3,4, maybe 500,000 miles on their cars. And I think the record is over one million miles. But realistically, lets take a vehicle with well over 300,000. How much money do you want to keep putting into this? What if they have $40,000 in repair & parts just to keep it road worthy? At what point should you give up on it? That's how & why cars die. Lack of interest.

As other have said, they don't really. It just gets to a point where owners decide to stop spending the time and money to repair and maintain them, or decide to sell them, etc. And most in junkyards, rusting in the ground or recycled into refrigerators may have been too far gone for restoration (and were not likely a model someone would spend the time and effort restoring).

I have kept four cars for over 200,000 miles (most were bought used, but I drive a lot). My favorite of those was a 2000 Honda Accord Coupe. That car got me through a lot of things and during a very difficult time in my life. But it was costing an increasing amount to keep going, especially as I took care of it, bought good parts, tires, etc.

But I knew it was getting up there and took some time to shop for another car while keeping the Honda going, but the engine seals had begun leaking along with some other issues that were going to cost more than the car's value. And, as I drive a lot, often at odd times and live in a place with long winters, I felt I needed something reliable. So one morning when the Accord didn't start for the first time ever, I knew it was time to go ahead and get another car.

Even after I buying the new car I still kept the Honda for a while, particularly as I knew that with a set of winter tires that car could get through blizzards which left most 4WD SUVs stuck. And I guess I wasn't ready to let go, particularly as I know what some people do to old Hondas. For instance, if I saw it ridiculously riced I would feel like I betrayed a friend. But one of my parents' neighbors needed a car, had mechanical skills and had helped my parents out with some stuff, so I gave him full disclosure of everything that needed done to it and sold it for $500. That was a couple years ago, and it's still going.

My 94 model is still going strong. At some point, probably if & when the motor or transmission goes out, I will have to make a tough decision because it might not be financially viable to repair it. (That is pay someone to do it)

Any car can run forever if you keep sinking money in it.

It's possible that you can keep any car running for years and years if you keep replacing parts. Just look at all the old American cars from the 50s and 60s in Cuba. But at some point, it just doesn't make sense to keep it up (except in Cuba).

The usual reason is the cost of repairs exceeds the value of the car. Older cars used to tidy badly but makers gave stopped my that now.
A major engine or transmission failure can make it uneconomic to repair.
Maintain it well and it will last. I sold a car which was nearly 50 years old and I had owned for 35 years.
It is how you look after cars that matters. I usually keep my daily driver 8 to 10 years then get bored and want something else.