Modern cars can, if treated well, run almost forever. Hitting 100,000 miles is nothing these days, and some motorists have rolled over a million.
That said, even well-maintained vehicles can send signals that it’s time to think about buying a new car (or a new used car).
Often, these signs are subtle – your car whispers rather than shouts. For the first few years of ownership, a new car is under warranty, and the manufacturer will repair major problems.
But once you get past 50,000 miles, unless you purchase an extended warranty, you’re often on your own. That means listening to your car and studying its changes in mood.
The daily diagnostics will provide valuable clues and help you decide when it’s time to say goodbye to your old car and hello to a new set of wheels.
1. Weird noises or smells.
The noises are worse. If you hear a CHUNK, any kind of grinding, or a loud rattle, not to mention old favorites such as a backfire and a coarse idle, there’s a good chance that you’re in for a costly repair and it might be time to get some new wheels.
2. Leaks.
3. Smoke.
4. Overheating.
5. Technology debt.
6. Shaky steering.
7. Pieces falling off.
8. A repair that costs more than the car is worth.
Two such repairs each year would cost more than the car was worth, so I was preparing to get rid of it and buy a new, more reliable car.
9. Awkward transmission shifts or declining fuel economy.
Dipping fuel economy is also a bad sign. If you’ve been getting 20-25 mpg combined from city/highway driving, then you drop below 20 mpg, you’re on the road to losing money every year.
10. Poor emissions tests.
11. The odometer is closing in on 100,000 miles.
Even if you been faithful about maintenance, 100,000 miles means a reality check.
12. You just made you last loan payment.

Now you have a clear choice: own the car free and clear and drive it until the wheels fall off or it’s worth next to nothing (see me and my Saab, above); or celebrate by trading in your old car for something new and start the process all over again.
If you do this every five years, you’ll always be in an auto loan, but you’ll also always be driving a vehicle that’s up-to-date.
If you do this every seven years, and you take out five-year loans, you’ll have two years of no payments. I recommend this plan.
[“source=businessinsider”]