My Leica M4 bought new in 1970 looks tattered, but still works well. Several Nikons and Nikkormats from that era have some problems. All were used hard and are fine camera systems. The Nikkorex and Nikon FM10 do not have the quality construction of Nikons and Nikkormats.
My wife bought me a FM-10 14 years ago and for about 9 years it was my only camera. I can not guess how many rolls thats been through it. Its looks rough but still works great. Its never been dropped, that I remember, but its had many trips to the beach and always rode with me when I drove cross country. If memory serves me, the newer one are not marked made in Japan, don't know if that means anything.
People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf.