Print is fixed. Digital is fluid. Almost every formatting mistake comes from applying print thinking to an ebook or the reverse.
Print requires exact specification
Trim size, bleed, gutter and spine width are calculated, not estimated. Spine width depends on page count and paper stock.
Ebooks require flexibility
Reflowable text means no fixed page numbers, no manual line breaks and a navigable table of contents.
Hardcover adds jacket geometry
Case wrap or dust jacket dimensions differ from paperback and must be built to the printer's template.

