I bought the car from a friend who was the original owner and had purchased the car when she was in college. It ran fine when I bought it, and aside from new tires, brake pads, batteries, and tune-up parts, the only parts previously replaced were the driver-side drive shaft and the timing belt.
The choke wasn't working and required quite a bit of cleaning before it performed properly.
The mechanical fuel pump failed a month after I purchased the car (140k miles).
To insure reliability for some trips across the country, I replaced the the radiator with a new one (old one had a crack that was fixed with solder).
I also replaced the head-gasket, water-pump, timing belt (first done at 95k, now at 140k), exhaust manifold which had a crack on the engine side, and exhaust flex pipe which was leaking.
The vacuum lines were nearly all clogged as was the EGR valve. They were cleaned or replaced.
Two of the vacuum control solenoids were also leaking and were replace.
The Secondary Air Control Valve (exhaust manifold to air filter) was leaking and after many hours checking salvage yards a replacement was found.