I'm a bit of a pack rat and almost never throw anything away that is working, or even fixable. I still have my very first SPG, a black-face Scubapro I bought in 1974. It still works fine, and is as accurate as any of my newer SPGs. This 40 year old SPG does not measure air pressure high enough for the equipment I usually use these days, but I did use it last year with an aluminum 50 cf tank, an old Mark V, no BC, a 1mm suit, line cutters, and 6 1lb lead bullet weights on a weight belt that has turned a lovely shade of green. Just playing around inside Barnegat Inlet, watching all the Butterfly fishes and counting seahorses. 14 on the remains of one sunken rowboat. Great fun to watch them hunt like tiny feline predators, flat to the substrate, moving into the strong current, separately focusing eyes twirling in their heads.
I can't understand people who complain about being cold in such warm water. 1mm of neoprene over a lycra skin is enough for me when local waters reach the mid 70s. When I was a kid I dived in this reasonably warm NJ water with just a bathing suit. Takes a few minutes and you get used to it. The old Scubapro SPG performed like the thoroughbred it is. Its biggest drawback are the countless scratches that make it a little tricky to read. When I compare its readings to current high end stuff it's right on the money. It will be a cold day in hell before I rely on a breathing gas pressure reading device that's powered by a battery.