I have learned that wetsuits shrink when hung in the basement in the dark.
{After 17 years of being a UW/Nikonos/Ektachrome photographer I quit in 1982.}
I learned that after 25 years of not diving wih a camera, after picking up a simple point-and-shoot Olympus, my entire diving style and process automaticaly changed... for the worse.
I learned that any diver who wears gloves in the warmest waters of the oceans has a ready reason for doing so, always capped off with "I never touch anything".
The same applies to divers (notably photographers) that use "muck sticks". They fall into the same category as glove wearers above.
I have learned that with the availability, low cost and ease of using digital gear, that besides every newbie wanting to drag one along on their first dive, after-dive chats have disappeared. No longer do we sit at the bar talking about what was good and what went bad on a dive. We are no longer doing post dive debriefs and bettering our skills... instead~ we sit and stare at laptop screens and look at the digital images captured from lifetime logged dive #4.
I learned that divers will buy mask defog for $15 a bottle even though toothpaste before every dive works 100%.
I learned that Titanium, the word or the addition of the metal itself to my dive gear, will make me a better diver.
I have seen an increase in the number of people who want a vacation with some diving, versus simply a dive vacation. I have seen a downturn in the "lets get diving" mentality of aging divers.
And yes, from the week-in-paradise perspective, I have noticed that the diving audience is getting older and more in search of creature comforts.