Mostly routine items as car ages.
3 alternator replacements.
One replacement of the water pump.
Rebuild of carburettor (which I now suspect was unnecessary as it was probably the fuel pump that was the problem, and I replaced that).
3 new mufflers under my ownership.
The main issue is rust, which is a problem having first lived by the ocean and now in the north USA.
I have replaced the 2 front doors because of rust and regularly spend time with a sander and paint to try to keep the car body intact.
The rear bumper also has a tendency to rust. I own two of these vehicles and on both this has been a problem. In particular there are metal bands that hold on the rubber bumper cover, and when these rust through the plastic bumper cover drops down in front of the exhaust.
Some wear in the synchromesh. Enough to cause problems in shifting when the engine is cold in winter, but disappears when the engine warms up a bit (and yes, the manual transmission oil viscosity is per the manufacturer's recommendations).
On my other 1981 Corolla wagon the power valve diaphragm (?) needed replacing. Spark plug #1 was not firing properly and was dripping in oil.
I have two 1981 Corolla station wagons, so it's clear I like them. I'm not a mechanic, but cars this old are simple enough for me to be able to do simple repairs of the unscrew it, buy a new one, screw the new one on type.
I get 25 mpg city, 30 mpg highway in the manual transmission car which I drive in the winter. The automatic transmission car, which I drive in the summer, does about 25 city, 28 highway. I look at new Corollas and see that they don't officially rate at all that much better, so these engines last as long as you look after them.
These are rear wheel drive cars, with little weight on the rear wheels, so handling in snow can be a problem. I have cats so winter is the time to stock up on 200 lbs of cat litter and keep it in the back of the car.
In my 16 years of driving these cars I have only been truly stranded once, for 3 days waiting for parts, with a failed alternator 200 miles from home. I have had a few minor strandings with dead batteries, but otherwise these are very reliable. One of my cars still has some of the original belts!
1.8 L engine is not going to have you burn rubber starting at traffic lights. With this car you learn to be a calm, patient driver.
The only problem I am encountering now is finding replacement parts. Small parts, like distributor caps, spark plug wires, etc., can still be obtained through parts stores, though they often have to order them. Recently though, my car was in a small accident and I needed to get a parts for the rear hatch as well as a rear bumper. Toyota dealers told me the parts numbers were no longer accepted by their computers. I finally found some replacement parts at junkyards around the country through the Internet, but a number of them told me that they had sent the 1981 station wagons they had to the crushers.