Well, I've had the same thing.
One year I had an American Standard Cadet in one of the bathrooms.
Worked well for several months, then bam!
It kept plugging.
I plunged, augered, took it outside in the yard and augered, got fed up and replace it.
If you have a toilet that constantly plugs, that an auger can't seem to clear, well, then replacement could be an option.
I don't know how much you want to pay a plumber to work with something that he can't get a good result with.