When I finished Glissando's restoration, I vowed to disassemble the prop shaft and coupling every other year to ensure that things would always be readily removable if need be, rather than have all the pieces become welded together as is common. Anyone who has fought with frozen coupling bolts and, even worse, a welded-on coupling knows how miserable this chore is, particularly in the depths of the bilge.
True to my vow, at the end of the second season in fall 2002, I disassembled everything for inspection and cleaning. It was suprisingly hard even after only two seasons but eventually it was all apart. I had assembled everything dry, as is common, and had used an unpainted steel coupling that came with my new Yanmar. I fought the coupling for some time before I finally freed it; even with good overhead access this was a terrible job, and I didn't ever want to repeat it. I cleaned everything up, painted the couplings, and thought about how to make disassembly easier in the future.
When I reassembled the shaft and coupling (and other parts), I applied a liberal amount of waterproof grease (OMC Systematched Triple Guard Grease in this case) to all the mating surfaces, hoping that this barrier might prevent the nuts from freezing, the setscrews from freezing, and prevent the coupling from welding itself to the propshaft.
I applied the grease to the end of the shaft, the inside of the coupling, the keyway and key, on the threads of the studs on both sides of the drivesaver donut, and on the propshaft threads for the prop nuts (and the keyway and key). Then I reassembled everything.
Click here to see that process from 2002.
Last fall, 2004, should have been when I disassembled everything again, but I didn't get around to it. Therefore, today, after three seasons of use. I disassembled everything. The prop came off hard, since my prop puller isn't that great, but that's not the prop's fault.
I'm happy to report that the rest of the assembly fairly pulled itself apart, thanks to that waterproof grease. The nuts securing the coupling to the drivesaver, and the drivesaver to the transmission coupling, came off easily; the setscrews came out by hand once the mousing was removed; and, best of all, a few light taps on the coupling with a deadblow mallet easily removed the coupling from the shaft, so there was no need for any annoying spacers and tedious bolt-tightening. I was thrilled.

Now that the assembly is apart, I'll clean everything up, repaint the coupling, and reassemble with more of the waterproof grease.
I would highly recommend that anyone with their coupling/shaft taken apart take the time to apply some good waterproof grease to the mating areas. The grease in hidden areas was almost like new and had not deteriorated at all. I was pleasantly surprised by how effective this coating of grease was; it exceeded expectations and even my most hopeful predictions.