This came from a discussion at my shop along the same lines as your last comment Greg. I was always told it was the length of he dive and not depth. If you are doing recovery work in 10 feet of water but down for 25 or even 55 minutes does that count? I say yes. Also as a divemaster working with instructors I am constantly underwater in the pool and I log dives in the pool over 30 minutes. I was lead to believe that any time you could suffer DCS (such as repetitive dives to 15 feet for 30 minutes with no S.I.T in between) should be logged. 4-5 dives in the pool might put you there. Far fetched I know but just an example. From the answers I’ve seen here there is NO definitive answer to this question as every answer is unique and correct. I don’t log down and up dives. i.e. hooking in a buoy line or setting up for pool dives. I don’t log any dive under 10 minutes no matter the depth. I don’t log free dives. I log any dive that I believe has a residual nitrogen loading time. A dive to 15 feet for 30 minutes for example has that as does a 10 minute dive.