A good OEM converter can easily last 7 to 10 years or more, but that depends on how the motor is maintained along with other factors. Poorly running engines will clog and destroy a CC. If it was an aftermarket and made with poor quality steel it may fall apart sooner. If salt on the roads during winter or from sea spray is a factor, then corrosion from without can shorten a lifespan.

Depends!

Thanks , I think between you and most everyone else I will be able to get a handle on it

In case you were wondering, charsley99 sums it up.

Forget what everyone said. Just read post #1.

The easiest test I know of for a restricted cat is a vacuum gauge. If the vacuum gauge moves toward 0, or goes into pressure, as you drive, it is restricted. Any part of the exhaust can be restrictive, but the cat is the most likely suspect.

There is no really good answer to your question. I have seen cats last well over 200,000 Miles, if the engine is properly maintained. The life of the cat really depends on the vehicle maintaienance, they quality of fuel that is used and that the correct oil is used in the engine.