Typically, the catalyst life is in the range of 100 thousand kilometers, but under fault conditions of the ignition system, improper feeding of a mixture or low-quality fuel resources is significantly reduced.
The catalyst, which is inefficient and has already spent its service life, must be replaced. And that replacement of catalytic converter is a very touchy subject for each owner, as new catalysts are quite expensive because of the content of a precious metal. Plus neutralization modern systems is a receiver in a tube consisting of catalyst in a body and the exhaust manifold and replacement is subject to not only the catalyst but also the whole structure completely.
Due to these factors, the replacement process is very laborious and expensive, which leads to the fact that most car owners simply get rid of unprofitable neutralizing device, without installing the new one.