The Need for Document Duplication

The media upon which documents are inscribed, they just inherently deteriorate. We want the information to last beyond the life time of that particular physical medium. Documents were also copied in the course of scribl training and resulting duplications may have found their way into private archives. i wonder if some of the texts that came through from the ancient world in plentiful supply actually came through because they were like example texts the ble practised copying text on.