The only reason I have decided not to purchase an older vehicle from owner is because I do not want the unexpected expense of more repairs.
Would you rather have an expected expense of $15,000 or an unexpected expense of $400-1000 if something stupid breaks on a not-as-new car? (Anecdote: my dad bought an '07 Nissan with 84k miles for $3700 two years ago. Last year he needed to have major engine work done to the tune of about $900. My mom bought a brand new car for ~$20,000 around the same time and has had no problems. My dad is still ahead by far. My mom probably feels bad for him and thinks he got a lemon. Her costs are larger, just less visible.)
Also, brand new cars are not even the most reliable cars; the statistically most reliable cars (due to the bathtub curve) are 1-2 year old cars. But you don't even "need" that for simple piece of mind. If you did, would you just buy a 1-2 year old car every two years? No, that would be madness.
If unexpected repair cost is your main concern about getting a used car, try thinking about it that way.
If you're not mechanically-inclined and don't know anyone that is, you can still alleviate that fear-of-the-unknown. Get any used car you're considering checked out by a mechanic before you pull the trigger. They'll probably charge about $100 for doing that, but even if you have that done on five different cars before you decide on one, that $500 is still way way less than shelling out for a brand new car.
Your '99 is dead and you want something newer. Something like a 2010 will still be way newer and nicer, but a lot cheaper than a 2017. I recently went from a 1992 to a 2009 and it seems like the pinnacle of luxury. Some quick searching on my local Craigslist finds me plenty of 2010 Hondas with 70k-90k miles for around five or six grand. If you go slightly "off-brand" you can find even better deals (newer or cheaper) on something like a Hyundai or Nissan.