A catalytic converter can be ruined by a engine that is missing and dumping raw fuel into the converter.
A catalytic converter may last the life of the car. There is no set time to replace it.
Two. One before, and one after, the catalytic converter. The one before the catalytic converter (closer to the front of the car) is more critical and usually first to be replaced, although both have a recommended replacement interval of 100,000 miles.
80k miles
What year is it? I had mine replaced on my 02 Regal at the dealer for free! They said it had a recall for the catalytic conv that covered it to 100,000 miles. Nice surprise!
Converter warranties seem to be 8 years or 80,000 miles.
It should last the life of the car if you maintain the car as you should. Let the engine start running rich and do nothing to repair this condition and it will destroy the converter. But keep the engine tuned up and running as it should and you will never have to replace the converter. NEVER had a problem with my 1996 HONDA ACCORD engine and CATALYTIC CONVERTER needed to be replaced at 220,000 MILES.
They are built to last the life of the vehicle if the vehicle/engine is maintained properly. What destroys a catalytic converter is an engine that is not running right and is ignored.
Generally, unburned fuel getting into the converter is what damages them. How is it running?, what size engine? What did the dealer say is "wrong" with the converters they are replacing? -->You can easily damage your catalytic converter by making a lot of very short trips and not allowing you car to properly reach operating temperature.
8 years or 80,000 miles.
Normally 8 years, 80,000 miles.
I had a similar trouble on a 2000 Odyssey. I replaced the egr myself, but the trouble returned. I then had Firestone check it and they did the same thing and cleaned the port. However the check engine light and the same trouble code kept coming back. I took it to the Honda dealer next and the they replaced the egr valve (again) and the catalytic converter (there was a code for the catalytic converter also.) It was all done under waranty with no charge, I had 78K miles and the waranty expired at 80K miles. I am now at 114k miles and have not had that problem again. Good luck.
8 years or 80,000 miles.