I buy new with the intent to drive my vehicles until the wheels fall off. That way I can get exactly what I want, I can maintain it to my specifications* for the entire life of the vehicle, I know the complete service history, can hand wash it from day one, etc, etc. Sure, I could buy a 10 year old vehicle for a lot less. But I'd have to buy twice as many of them, 'cause they're all half wore out. Which means I'm having to go car shopping twice as often. And then you have to spend time weeding out lots of crappy ones from the good ones. Did they ever change the transmission fluid? Did they smoke in it? Why didn't the ad say anything about the rust on the frame? And then there's fixing the inevitable deferred maintenance items, which takes more time and money.
And, yes, I have gone the buy-used-save-a-bundle route. I bought a 10 year old Jaguar XJ8 that had 35,000 miles on it. I had to immediately drop $3000 on it to prevent the engine from grenading itself. I owned it for 5 years and it was by far the best car I've ever owned and had the cheapest total cost of ownership, including the $3k in preventive maintenance. But I have 4 kids now and a job that pays well but requires a lot of overtime. I don't have the time to invest in buying used cars right now and the potential savings is less than the opportunity cost of spending that time not-at-work.
*I don't care what the owners manuals say! I want my transmission fluid changed every 3 years.
That's one of the few ways to actually get your money's worth out of the vehicle is to keep it many many years. It reminds me of my dentist who was my dentist for a little over twenty years until he retired. He knew it was in the cars and when he was getting ready to buy a new SUV he asked me for my opinions on the newer models. The last vehicle he purchased was about a 99 Suburban and he had it for 16 years. He was ready for a new one.
Now, this was a man who lives in a very big expensive home and had lots of money and I'm quite sure his retirement was funded nicely.
Having the latest and greatest or showing off his car was just not important to him. He simply wanted a good Dependable transportation and like the extra room and hauling capacity and SUV provided.
Everyone has their preferences. Changing transmission fluid every 3 years it would always look like fresh new fluid. I guess that's your point. Not necessary and it won't make your transmission last any longer than if you changed it every five or six years but it makes you feel better so no big deal.
I've known people who change the oil every two to 2,500 miles because Society was convinced you're supposed to change your oil every 3000 Miles so they want her to do better and do it every 2002 2500.
After 30 years we find out that was all a hoax and a scam! They just wanted to be able to build the Empire of Jiffy Lubes and quick change oil places which popped up on every corner.
People were changing perfectly good oil with 60 to 80% of its life left just because of an arbitrary number of miles or months.
People who changed the oil at 2500 miles we're not having their engines last twice as long as people who were changing the oil at 5000 miles nor were they having fewer repairs.
But for some of us, it's like a motorcycle. It gets the oil changed every season whether it needs it or not.