There are various styles of writing.
Some writers work out the plot, content and flow in detail, in a pre-document framework or skeleton, before they start writing the actual manuscript – be it fiction or not. P.G. Wodehouse was of this type. He says “Before I start a book, I’ve usually got four hundred pages of notes. Most of them are almost incoherent. But there’s always a moment when you feel you’ve got a novel started. You can more or less see how it’s going to work out. After that it’s just a question of detail.”
In this case, there is not much rewrite, as there is filling in the flesh onto the skeleton of ideas, and fine tuning in due course, with a few rounds of edits. This is apparently how the masters of the past created their masterwork. Thus, in these cases, the entire writing process is divided into three tasks – the prep work, the manuscript creation, and the review.
Other writers get a spark of an idea and they put it down into words in a flow of wild abandon – the stream of consciousness, as it is called these days. In such cases, there is no separate prep-stage, but the manuscript creation itself builds the plotline or concept. Then, they go back read, re-read, re-re-read and so on, axing words here, moving things around there, making sentences sound better, etc.
The above style of writing is largely a result of the use of computers, where it is easy to go back and forth without having scratches, overwrites and such inconveniences.
The computer has also introduced another style of writing, in which, the prep stage may or may not exist, but the manuscript creation and review are intertwined. As the manuscript is being created, the writer periodically goes back and forth, checking for continuity and flow, moving things around, fixing idea mismatches, etc. There may or may not be a consolidated review process at the end.
Whichever be your style, the review/editing process is important, not only to eliminate errors, but to also tighten and polish the manuscript. Good writers never hesitate to “kill their baby” – a term coined by Ernest Hemmingway for the process of deleting (obliterating may be a better word there), words, sentences, paragraphs or even chapters that don’t add value to the creation. Mark Twain said “Writing is easy. All you have to do is cross out the wrong words”.
Finally, the writing or the editing process cannot be endless. Most writers agree that with Paul Valery that a writing is never finished, only abandoned. The truth, as most writers and editors know, is that the more number of times you re-read a work, the more corrections and polishing you can do. At some point, you simply say “ok, I am done” and throw in the towel. Perfection is not only subjective, but also relative. So, not publishing until the manuscript is perfect, is like doing only doing research that leads to a Nobel, which in Ramon-y Cajal’s words is a “disease of the will.”
"As if believing in miracles, they want to start their careers with an extraordinary achievement. Perhaps they recall that Hertz, Mayer, Schwann, Roentgen, and Curie began their scientific careers with a great discovery, and aspire to jump from foot soldier to general in their first battle. They end up spending their lives planning and plotting, constructing and correcting, always submerged in feverish activity, always revising, hatching the great embryonic work—the outstanding, sweeping contribution. And, as the years go, by expectation fades, rivals whisper, and friends stretch their imaginations to justify the great man’s silence.
Ramón y Cajal in his 1897 book Advice for a Young Investigator