you can copy elements in interface builder, iirc. you can't copy their constraints, which makes sense because the copied instances necessarily have different constraints. otherwise the copies would just stack on top of each other.

in my personal opinion, IB is great for layout of one view or screen, especially with the new IBDesignable and IBInspectable features.

doing app navigation in a storyboard is a terrible idea and will lead to a monolithic storyboard file that is very annoying to work with.