I bought the first one about 12 years ago.  We learned after about 8 years that if the stove is too hot, the result is the insert surface bubbled and peeled.  We bought a new insert.
Last year on year 12, it stopped holding the temperature I set it for.  It would continue heating but at a very low temperature.  After  fall of if that, we bought a new one and kept the old insert which I am using with the new slow cooker