Not that many years I'll tell you. Long enough to be able to tell stories of "now that was a stupid move, wasn't it" - like just last weekend on the last qualifying dive for my Navigation course, the team agreed on the plan, signaled to descend..... and nothing happened. You know you don't descend very far without a weight belt! Wait, wait it gets better. Just before this we had been doing a snorkeling exercise mapping out the buoys that we were about to navigate underwater. As there weren't too many people left at the dive site, we had locked some of our kit in our own vehicles (I put my weight belt there), but the BCD/tank were all but in a van. We got out, put our kit on, I locked my keys in someone's vehicle and jumped in. When I discovered my problem, and stopped laughing, I asked the last one on shore to help. He said sure, where are your keys? I replied, in your van, where are your keys? He started grinning -- with the diver that just descended! I had to wait until she noticed there was a problem, for her to ascend, stop laughing and pass the key over.
Saw them last night at the pool, and while getting ready to get in, she asked "now have you got everything this time". (geesh, friends) People around us couldn't understand why we were laughing so hard.
What did I learn? Buddy check all the time!