One of my TCD-440A's arrived with me non working and I never got round to fixing it but the other one and the TCD-320 were used on and off for 5 years or more with no issues. Cassette was never a big source for me so they prob only got an hour a week use though...
I only used my CR-3 for recording tapes for the car. In the mid 1990's car CD-player became good enough, so it has mostly rested since then. Probably used 25 hours, or so.