It depends on the car model and how the specific car is maintained. The rule of thumb around 1985, according to a Reader's Digest generic car repair manual which I studied closely to get an idea of how new engine control technologies were supposed to work, was that a car could be expected to last 10 years/10,000 miles with ordinary maintenance but 20 years/20,000 miles if it were "overmaintained" (i.e., service intervals were halved).
My last car was a 1986 Nissan Maxima, handed down when it was 10 years/62,000 miles old, and disposed of (by donation) when it was 21 years/227,000 miles old. In this model the engine lasts virtually forever as long as the oil is changed (Mobil 1, new oil and filter every 3,000 miles in my case) and the timing belt is replaced every 60,000 miles. It is, however, rare for the automatic transmission to live to 200,000 miles without a full rebuild. Mine never needed a rebuild or even repair because I ignored the factory settings in fixing the shift points, and also used an undocumented drain-and-fill procedure to change out the fluid every 15,000 miles. (In theory the transmission fluid needed no changing and the transmission would have acceptable life at the factory shift settings, but in practice neither was true.)
On the other hand, I have a high tolerance for ugly cars and it has gotten higher as I have gotten older. The Maxima looked pretty terrible when I finally got rid of it--peeling paint and noticeable discoloration of the upholstery in the driver's seat. (I drove Arizona I-8 during the day in September 2002, using ice water in a thermos rather than the air-conditioning to stay cool. The sweat lifted the dye in the shirt I was wearing and leached a lot of the color out of the seat. I don't recommend this kind of driving without old clothes and a towel over the seats.)
