I used to do a lot of diving, but not so much any more. I think that my oldest C-card is probably from the early 80's. My newest card has a picture glued to it, & was hand typed cardboard that was then laminated.
Somewhere I should still have an old Dacor double hose regulator
with adjustable venturi & my first single
hose rig, which was a cousteau-gagnon aqua lung with a pop pin pressure gauge. I miss the old Princeton Techtonics bottom timers. I wish that I could still get rebuild
kits for them. I tend to trust things that are rock simple, the way that they were.
When my wife took a class to get certified, I tried to help her study. I quizzed here about numbers on the dive table off the top of my head
. After I told here that she was wrong several times, I went to show her how to look things up & found that the numbers had changed. The sport tables are no longer based on the Navy
tables. The sport numbers are more conservative now. Since I have over 30 years experience & over 600 dives with no bad bottom-time-related experience, I still dive on the same Navy
tables that I have always used.