A recent discussion on here about whether or not program windows should still be called screens or if we should have improved terminology got me thinking... Dangerous I know! People as a whole tend to be fairly resistant to change. We get comfortable in our niches and used to the way things are. While some changes lead to good results and improve our lives or the way things are done, others are clearly not enough of a change or overall bad and not even worth attempting. What guides can we use as we program to determine if an improvement (whether it be to coding style, terminology, user interface, language use, etc) is really an improvement or not? I'm sure to some extent nothing will replace the try-it-out approach but are there any tests or guides that can be used to eliminate certain ideas that would eventually turn out to be worthless or a waste of time to pursue?

EDIT: For anyone who is wondering the discussion that brought this question up in my mind is found here: Does your organization still use the term "screens" to describe a user interface?