An interesting question... when I was originally certified it was only because shops were starting to require a C-Card to get air. Took the YMCA course in '71, AFAIK there were only two Scuba ratings - Scuba Diver and Instructor. After certification the only reasons I saw the inside of a dive shop were to get air and the occasional new rubber band for my spear gun. I was an occasional recreational diver until I bought my own compressor, then it was to the dive shop only for rubber bands and once every five years for a hydro on my tank. It was in '95, I think, when my reg started breathing really wet that I went to the local dive shop to buy an exhalation valve for my 24 year old Conshelf, expecting to spend a couple of bucks for the valve.
You'd have thought I'd asked 'em to rob a bank! "This is life support equipment! We can't just sell you parts! We'd be LIABLE if anything else failed on the regulator! Where's your octopus? You need an octopus! We have to overhaul that reg before we can ... do anything!"
Long story short, before I'd left the shop, in addition to a regulator overhaul, I'd bought an integrated safe second, an "Advanced" class for me, an OW refresher for my bride, and a Blackbeard's cruise for 2!
So, the answer to the original question? 24 years.
But I have to put in this little tidbit - I found the "Advanced" course fell far short of the '71 YMCA course in many ways (as there were no BC's or SPG's or Safe Seconds in the '71 course it's not a straight apples-to-apples comparison - and no running laps and doing push-ups with a tank on my back in the advanced course!).
Rick
