When a car reaches 100,000 miles it's getting into the high mileage territory.
However a car that has 100,000 miles is not yet really high mileage and you can expect a good maintained car that has 100,000 miles on it to last another 100,000 to 150,000 miles and sometimes longer.
My car has over 200,000 miles and has been maintained and I'm sure it will last another 100,000 miles at least.
If it were to go out now at 230,000 miles then I wouldn't complain as I bought the car used when it had 100,000 miles on it.
It's been a very reliable car and I got it for $4,000.00
Just make sure the car is in good condition and have a good mechanic check the car over before you buy it if you're buying a car with 100,000 or more miles.
But just because it has high miles doesn't mean it's a bad car.