Try to stay away from the analysis paralysis. I've owned and used the same 124G since purchasing it new when dinosaurs roamed the Earth. Although admittedly lightly used, it still works (and looks) like new. Those first two photos in that gallery search set are mine. One from the 70s and the other from about four years ago. There was no difference in camera performance between those exposures.
Oh, and several years back I asked a camera repairman to calibrate the internal meter. At first he looked at me like I was crazy, but I insisted. Since then that meter has worked dead on. It's completely accurate and reliable as long as I use it in the reasonable middle of its range. (I do still use only original PX625 mercury cells in it.)
I'm reminded of the signature line of fellow APUGger 'darinwc':
"Go not to the elves for counsel, for they will say both yes and no."