Converters have two failure modes- chemical and mechanical. Chemical degradation is indicated by failing emission tests and all other emission control equipment and operation checks out okay.

With enough thermal cycles the honeycomb matrix can break apart and either cause a rattle or loss of power due to plugging the exhaust system.

Bottom line: There is no need to replace it unless and until one of the two above conditions is positively confirmed or until the shell burns through causing a leak, but since it's stainless steel, burn through is not common.

Duke