Producing a PhD is normally a longer piece of writing than anything you have ever done before. If you have to tackle a ‘big book’ thesis then it may easily be the longest text you ever complete, even assuming you enter an academic career and keep writing for another several decades. As a university teacher you will rarely get three or four years again to work full time on a single research project. Perhaps you will publish books, but most academic books have to stay between 60,000 and 80,000 words long, while 'big book' theses can be up to 100,000 words with students typically taking it to the limit. Even where your doctorate has a papers model dissertation, this will normally be because your discipline's dominant type of academic publication is journal articles. And so your dissertation will still be four, five or even six times more text than a full paper. It may be equivalent in length to four years' academic research output in your later career, but all wrapped up together in a single pair of covers. So the simplest reason why it is important to think systematically about how to author a doctorate is that producing this much joined-up text for the first time is unavoidably difficult. The longer the text the more taxing it becomes for you as an author to understand your own arguments and to keep them marshalled effectively.