The baffle is a consumable item that should be replaced as and when it is needed.
Our small cast iron stoves have a very long lifespan if the consumable parts are replaced when they have become worn. The baffle can break if you are letting in too much primary air through the centre grate. This can lead to a very high temperature in the combustion chamber, and this can shorten the lifespan of the baffle.
The baffle can also break if there are ashes and soot sitting on top of the baffle for a prolonged period of time. The baffle should be removed once or twice a year, and the soot and ash can be cleaned off with the use of a brush.