More often than not, the ceramic rings do not make it to expiration of the useful production life. The more likely scenario for replacing them tend to be mishandling. The rings will often be set down incorrectly or dropped causing a chip in the ring that renders it unusable.
If the ring is to make it to the end of its useful production life, one of the symptoms is heavy shadowing of ink on the cliché. The lapped flat, when new, is approximately 0.005″ wide. When the flat wears to a point where the mean width approaches the 0.010″ to 0.015″ width, you can safely say the ring has served you well.
In my experience you can see upwards of 5 – 6 years of useful life out of a ceramic ring (dependent on usage).
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