I find that the more often I drive my 2001 ETC that the car performs better each time I take it out of the garage.. I realize we are dealing with 18-year old parts, and they will eventually need replacing, as they would need the same in any car that old, but I watch it closely and keep a reserve in my savings just for this. I really love that car.
I would like to add that it is not my daily driver because it lacks the really cool electronic safety features my 2019 car has. Although fun to drive, it requires way more attention to detail when on the road, and in parking lots. So, I take it to car shows and club tours, but let it rest the rest of time.