In any primary user interface screen, a designer must find a balance between too little and too much information.
Often, adding additional status information is cheap, technically. Therefore, some (not I) believe: If we can show it, why not?
More information is always better.*
At some point, though, the delicate balance is lost and the view becomes too noisy — even if there is "space" to put it all, the presence alone of information that is infrequently used causes user friction when trying to quickly take in the more important information.
So, how do you find the right balance, and how do you know when you are exceeding it? When designing a primary user interface screen, how do you decide whether additional information which could be added to the screen is actually a net negative?
* Note: the question is not intended to simply ask for arguments against that statement - I think most designers already agree that its false. It's about how to find the balance — whether that "more" is bad or good.