Data is forever. If you've got a working model (and system) for Users, Widgets, Gizmos and Sprockets, then there's little reason to change. New client devices

Data is forever. If you've got a working model (and system) for Users, Widgets, Gizmos and Sprockets, then there's little reason to change. New client devices come and go though, and users expectations of a good interaction experience change, and once your backend is solid you can quickly throw a new skin over it and view/interact with it in a new way.