One issue I have is probably silly but hey....
On a boat there are few places or directions that dont need watching at least occasionally....so I torment myself with how many cameras are needed for the coverage I want.
Without super duper cameras that have either lots of functions or are mythical.....ones with huge fields of view, great range, fine detail, all weather and light capabilities, etc....
I will probably just wind up with 2.
1 engine room and one aft facing for lower station docking and passing traffic.