I was an Army diver, when I attended training in 1992/1993 the Army still went through the Navy course. My last tour of duty was at the Naval diving and salvage training center 99-01
The Navy has a wide variety of divers, divers are also responsible for maintaining all of thier life support equipment (compressors, chambers, helmets, SCUBA, communications, etc) so a portion of the time is doing maintenance on dive gear:
Sea-Bee divers do construction and demolition projects in marine environments, friends I have in the Sea-Bees dive pretty often until they get higher in rank then much of the work is project management / bidding new projects.
Saturation divers - most of the work now is at NEDU in Panama City Florida, one recent project in open water was the saturation portion of the Monitor recovery. The size of these systems require even more maintenance than the basic equipment but they have a support force of civilian techs as well (most are former military / saturation divers)
Deep Sea - Navy divers work a pretty wide variety of posts from units specifcally for salvage operations (MDSU), instuction billets, equipment support for SEAL, special operations, EOD units, and ship husbandry units. Most of the units are pretty heavy on personell but new newer divers get plenty of work.
Most of the busy divers in working units average between 100 and 200 dives a year, in training units you can exceed 300 dives a year but they are often monotonous / safety diver.