If anyone wants to indicate at every junction or lane change, etc, then that is their choice, they are not wrong and should not be criticised.
On the above about roundabouts, it's not only following vehicles. If I see any vehicles either in front, behind, or any pedestrians who may need to know my intended roundabout exit then I will always indicate.
For me though, if I don't see any other vehicles at any of the roundabout entry or exit points or pedestrians then I don't indicate, no point, no one to tell.