The LAST TIME that I did a full service was a couple of decades ago when I thought that the line in the user manual about a regular full service sounded like a good idea.
So, I sent my Nikonos V and SB102 to the local Nikon service centre. On return I did a test in the bath then went diving. The camera flooded past the internal o-ring around the shutter-speed control shaft. Just a few drops but enough to fry the electronics. The strobe had a wire pinched against the case wall and would not fire below 5 meters deep.
And, guess what? Nikon accepted zero responsibility.
Since then, I have always employed an "ain't broke, don't fix" approach.
But, I do take great care with my housings: plenty of fresh water soak time, careful o-ring maintenance.
One of the things that I like about the BS Kinetics housing is that it only has two o-rings and they are both easily checked.
Regards
Peter