help Identify age of capacitor?

1973?




Screenshot 2023-01-27 at 09-35-07 Sprague Powerly Tic 36DX 17000 uF 75DC Capacitor NEW with Mo...png
 
I use them regularly because I have a lot of them in stock (old ones), I gently revive them for an hour or two with a stabilized variable power supply.
I don't see a lot of "before/after" ESR change but I do it on principle.
 
True of course, but it is an easy inference from the previous data. It also depends on the way they are used, but unlike modern, subminiature Ecaps used in modern-day switchers, they are normally not pushed to their limits.
I have used a number of them in my permanent lab fixtures, and they have lasted for some decades. They were not pushed to their limits though, and that's probably the aim of the game with those: they are substantially oversized, and "chi va piano va sano, e va lontano".
I have had one or two unpleasant events with these computer-grade caps (not this precise brand), but generally they are bound to outlast you and me (me, certainly)