Catalytic converters are more than just filters, they reduce the toxicity of emissions from a vehicle's combustion engine. The first models of these catalytic converters came in 1975 on series-production automobiles in response to the tightening EPA regulations on automobile exhaust. These first used pellet-style catalysts. But now, catalytic converters are made with a honeycomb design that makes these more effective in changing gases to more environment-friendly gases.
Since its earliest conception, catalytic converters have done an important job of preventing noxious gases from continually polluting the air. But, catalytic converters don't last that long. Every moment you drive your car, the catalytic converter seeps all the gas that the engine produces. Imagine all the fumes that the it has to endure. These really need to be replaced if they're worn out. If you won't, your local police might get you. These need to be replaced to be able to pass your local emissions test.
If you are in the situation that your catcon has broken down, it is better that you take a new replacement but not from your local dealership parts counter or they'll really milk you dry. OEM catalytic converters are so expensive. It is much more advisable to find a OE-fit catalytic converter replacement which are much cheaper that OEM replacements but function just as the same.