I have used my Futaba 14MZ for 10 years. But this summer the throttle potentiometer gave up. (I have on loan a clubmates 14MZ now since he use 18MZ).
Otherwise my 14MZ has worked fine.
I will have my TX reparied by Futaba service guy in my country later in autumn, and also change rest of stick potentiometers and the internal battery at the same time.
Changed many of the Li-Ion batteries for this TX during the years of course since they do not last that many years with good capacity.
I had hoped Futaba would come with a replacement for 18MZ/18MZ WC and maybe such radio could replace my old 14MZ.
I will wait a little and see what Futaba might release in the future.
It feels that 10 years might be a reasonable limit for any TX to start thinking of retire it. I got the first sign now with the throttle potentiometer on mine.

/Bo