It depends. If you’re only a millionaire on paper mostly due to your house then yeah… enjoy that second career. You probably need a couple million (liquid) to have a comfortable retirement.While I tend to agree with you about spending on cars, the term millionaire doesn't carry all that much weight anymore. If you are my age and not a millionaire at least one time over, get ready for that second career as a Walmart greeter.
I used to swear by purchasing late-model used cars, and I agree that it's still the smartest way to buy. But at some point I just found those vehicles very hard to find, so my strategy in recent years has been to buy new, affordable cars and drive them forever. Okay - not quite forever - but I recently kept a couple of vehicles for 16 and 17 years. That probably still costs more than buying a 2-year-old vehicle and keeping it 10 or 12 years, but I doubt that it's a huge difference.
I’ve had good luck finding the car I want 4 -5 years old with under 30k miles. My last example was bmw 3 series that was four years old with 27k miles on it. Was $57k brand new.. I purchased for $18k… it has 130k miles on it now and I’m still enjoying the vehicle