I've been wondering, at what point should I give up the convenience of a static data entry form with designer support for a dynamic UI which removes a lot of code duplication?

There seems to be a conflict in the programming world where people constantly try to remove code repetition to improve maintainability and yet when it comes to forms, that all goes out of the window and everything gets added explicitly to the forms.

What signs should I look for to know when it's time to leave the designer in the dust and create a dynamic UI?