We're in California, so rust isn't an issue.
Tis the difference between you and me. I'm in Pennsylvania and rust is an issue.
In the past we've purchased 5 year old cars, paid on them for 5 years, then kept an additional 5 years while paying for the 2nd car. Hence, we keep a car 10 years and the cars are 15 years old when we get rid of them.
That is the problem. 15 year old cars with 200k miles and rusted to scrap are not worth anything, thus the replacement needs to have a car payment. With interest rates on used cars, the payments are nearly what a new car is anyways. So now my wife's car was bought new, we will pay for 5 years, keep for 5 years, then trade and get a few thousand out of it as opposed to the $50 and $300 I've gotten out of my previous 2 car trades.
I do my own work on the cars. It's difficult to think to shell out $900 for a repair after you find out it will be $20 for the gasket, $30 for the belt, and about a weekend in the driveway to do the work. That's $850 for the labor in the shop and I still don't have a car all weekend or for the equivalent of 2 days.
Problem with that is in keeping a car with above 150k in the snowy areas. Bolts are rusted on and these $1000 jobs start to come up more and more (head gaskets, timing belts, water pumps, clutches, etc.) You either start paying constantly or you end up working on the car constantly. Some things took much more than a weekend for me. A head gasket or clutch is pretty simple work. Trying to diagnose an electrical sensor problem can put my car down for months.
Then obviously there is the rust problems where I live. Anywhere after 150k miles you can expect the rust to start sometime. It can surface at 150k or it can wait to 200k, depends on the car. But once it comes, there's no getting rid of it. You can temporarily fix it, but it will come back shortly, even with a professional job.
So that said, we've come to the conclusion, we would rather buy a brand new $20,000 car and trade it for $5000 than do what we previously did and buy $15,000 used cars and trade them for nothing. Same ownership lifetime, same money being spent, just much less hassle when we get to the end of the 10 year ownership term for us because of a lot less big repairs.
Oh and one more thing that I thought of. I did make a big mistake in the purchase of the new car. I paid $18k for a new Ford, which I should have known better coming from 20 years of driving Japanese vehicles. I could have bought twice the vehicle for the same price used as I did the new Ford. So, my idea of buying new and trading for a higher value later is still up in the air. Thus far, I have more money and time in repairs to the new Ford than I've had in my last 5 used Japanese vehicles. Perhaps it would be better to buy the used and trade for nothing when they are rotted out rather than buying new because I have to downgrade the quality to buy new.