Hi,
I'm new, and not that Mustachian, so I've been lurking, but I know a thing or two about used cars so I wanted to speak up. You seem nervous about buying a used car. I've been driving for 10 years and during that time I've driven approx 300,000 miles. I've owned three cars, and all were at least 15 years old when I got them and the average age of my car at any given time is about 20 years old.
Lots of people are nervous about buying a used car because they are worried it won't be reliable. They think it will either break down frequently, leaving them stranded, or will be a money pit, requiring frequent costly repairs.
Suppose you need to be at a certain place at a certain time and you decide to drive there. There are three basic categories that any delay will fall into: environmental (traffic, closures, weather), driver related (illness, drunk, forgot to get gas), or car related (breakdown, won't start). People spend many many hours each year being delayed by the first two things and think nothing of it. A good used car, well maintained, rarely breaks down. My cars were bought randomly, without much skill, and maintained when I felt like it. I've only been stranded twice in ten years. How many times has traffic delayed you in ten years? Or weather made you stay home? Or you lost a contact or accidently drank too much? Your car would have to break down ALL THE TIME to delay you more than the things you already don't think twice about. Environmental delays are way, way more common than any other delay, followed by driver error, and used cars are a pretty minor cause of delays.
As far as the money pit goes, as long as you don't buy a car that has been tortured by a sadistic driver, you're probably going to be ok. Buying and maintaining my cars has cost me about 20,000 over the course of ten years. I can almost guarentee you've spent more, probably twice or three times that. I also have been told by all my coworkers and many of my friends over the last decade how foolish I was to drive older cars. But I noticed that they took their two or three year old cars to the shop just as much as I did. And they had payments and super high insurance, and they all got more tickets than me.
Your dedication and skill as a driver, plus a little random chance, affect your driving costs far more than how old your car is.