I bought a '91 Wrangler Renegade as a beater car about 2 years ago. I got it for a steal ($1900) and it's in excellent condition. Everytime I take it in to be serviced they praise how great condition it's in for having 118k miles. Needless to say, it's not considered a beater anymore. I love the car.
I just took it in to be serviced and heard a "tin can" noise. The SA told me it was carbon build up in the cat. They said I would need a new cat soon, but I won't fail emissions since it's not blocked. Well, I drive it less than 5k miles a year anyway and according to Pa standards, I am emissions exempt, and also, according to Pa, when a car is 20 years old it becomes emissions exempt--which will be next year regardless of mileage.
My point is, I won't need to replace the CAT since the car is exempt, but what do I have to worry about? It will get clogged one day, what harm does that do? What should I do, any recommedations?