Old vs. New

My automobile is several years old. It is very easy to to get and out of. Roomy enough to bring home all my purchases, even those boxes from IKEA. Registration and insurance are not a huge expense either. When I take this car to the garage to have some work done, I always tell the mechanic:"Tell me when I need to buy a new car!" So far the response is: not yet, it's still a good car. This week the car was in the shop, the symptom being those dash warning lights were on, and , oh ya, the interior light wouldn't turn off. There was a short, a wire was touching the ground. And those dash lights were on for a reason. How about leaking brake fluid and needing new rear brakes. Even though it was a costly repair, it was so much cheaper than making a payment of the same amount every month to a finance company for a new car.
How much longer can I make this car last?