regarding clutches:
20 years ago, I overhauled the engine on my 1952 Ferguson. The engine was tired after 40 years of heavy use, needing everything done to it.
I did a complete front to back, top to bottom engine overhaul and when I got to the clutch, I could see no reason to replace the disk or pressure plate as they were absolutely perfect. I did replace the throwout bearing. As far as I could tell, they had never been replaced, as the previous owner had it for many many years and had not touched it. There was also no indication that the engine had ever been taken apart.
I used it for about 20 years, put thousands of hours on it, and gave it to my son last year. I have never adjusted the clutch in all that time. As far as I can tell, it might be 60 years old and still going fine.
Unless someone is really abusive to it, they last for a long, long time.