Well I would first define your needs. If the car breaks down does it cause an immediate issue? As in, no backup plan to get to work and work is intolerant of transportation delays? Do you travel long distances in places where you'd rather not break down? Or is this a car that goes short distances (say, 5 miles) between places and you have access to bus services, a friend, etc. as a backup? Yes, as you approach 8 orbits around the Earth's equator, things will go wrong.. but if issues can be mitigated, I don't see a need to change things up.
You could have the car last another 75-100k or it could blow an engine tomorrow. Hard to know. If the car has no real value (like, sub-2k) running, as I suspect it does, I'd simply wait for a big problem to happen (say, bad engine, transmission, car breaks in half, etc.) and junk it for $300-400, activate your backup plan, and go shopping. If you do it right, you'll also have the cash saved up to be able to pay for the next ride without borrowing.
I think you are still in the sweet spot of low cost car ownership, a car with little value so dents and dings don't matter, insurance should be cheap, but still enough life left to be usable. Once something in that equation changes, then it's time to shop.