Since I have been diving off and on for almost 30 years I can add a little to the conversation, based on experience and some personal fact. Started in Okinawa in the late 70's, we dove alot during that time, plenty of ops and some very challenging dives all along the pacific thanks to Uncle Same. Most of us in my OW class dove together and we probably as a group logged 200+ dives each that year. Only 2 out of 18 of us went on to AOW and they said it really didn't teach them much more than we learned in our AOW, except giving them a few more dives with our instructors, who taught a very mean OW class, cost $50.00. Those who transfered to the west coast dove quite regular, those who went to the south and east coast seemed to dive a bunch and those of us (Me) who got stuck in Memphis, did'nt dive at all for 6 years. The two guys went to Hawaii dove thier butts off and today both guys are sitting on 3000++ dives and Master Dive Instructors. I'll try and make a point here, access to good diving probably keeps one motivated to seek new and more difficult dives, they'll most likely seek the higher level Certs, ( I would like to pass by AOW myself it is not worth the bucks to me.) Another aspect maybe how well they learned the basics and how confident and comfortable they are in the water, myself I have just a OW with almost 500 dives, (transferred to better bases) I didn't feel a need to get AOW. Now with that said, 9 of us still only have OW, 3 have AOW, Res, 2 our Master Dive Instructors, 2 we cannot find and 2 have passed away. Good news most of us still continue to dive and now that we are retired from the service we plan on diving more often, looking at 50+ dives a year. One other thing if getting your certification becomes way to easy, which I think it has, then there is nothing bonding you to the sport and no drive to dive, take it from someone who has had long periods of non-diving, when you have been bonded to SCUBA it eats at you until you get back in the water. Dive well and Dive often Semper Fi