Whether it is plugged in or not the relay mode does not change. It only changes when the "salesman switch" is toggled by a person, dog, cat or some other gremlin
.
There is one of these switches by the door and another on the driver console.
IMO you don't need to worry about exercising this relay to keep it healthy, especially the new Blue Sea units as they are sealed units designed for marine environments and are very robust.
The primary purpose of the switch/relay is to reduce power consumption when you are not plugged in and are not actively using the coach.
Note that the other switches switches and breakers as shown in the photo post #5 (2017 and up) should all be turned off for very long term storage.