My passport is so tatty, I'm well beyond worrying about its appearance. It's in my front trouser pocket for take-off and landing, and all the time when I'm away overseas. The gold lettering is long gone and the cover scuffed. 'Well worn' would be an understatement.
Best description is probably that its like an old, dented and bruised car. Any new 'dent' just removes or covers up an older one