I have a rental unit that I have had to replace the cartridges almost every 2 years. Last month I replaced 2 for new tenents. One week later I was awoken at midnight as my tenent went to take a shower and the handle and cartridge came shooting out and hit him in the chest.
We called a plumber the next day who said it was just a washer. Then 3 days later the same thing happened again. Calling a different plumber this time we found that the cartridge was defective. I had him check the other bathroom as it was leaking and found that that one was also defective. Good thing that one had not blown out as it was in the bathtub and would have hit one of the children right in the face! I'm ready to tear out the plumbing so I can get another type of faucet.