From Writers Helping Writers:
Unless you wrote your book exclusively for your own satisfaction, once your creative vision is on the page, it’s time to zoom in on how the book works for readers. The key is getting the right kind of feedback for where you are in the revision and editing process—and dodging the kind that will pull you off track.
Much of this choice hinges on your editorial budget. You could do most or all these steps for yourself at no cost, but the quality of your book will reflect the quality of the production behind it. Most writers end up drawing on both free and paid feedback options.
Writing Feedback: Stage by Stage
With a newly complete manuscript Volunteer feedback is perfect at this stage of your book’s development. One or two alpha readers (often a spouse, critique partner, or close friend) provide that initial gut check on what’s hitting home and what’s missing the target.
During second and later drafts
As you continue working through early drafts, crowdsourced feedback continues to be your best bet. Lean on your peers in critique partners and groups, collecting enough opinions to sort out which point to genuine issues and which simply refer to personal taste.
Active drafting can be an opportunity for coaching or mentoring on story problems identified by critique buddies—a character arc that refuses to gel, saggy pacing, a general lack of zing—if your budget and time comfortably allow it. A little one-on-one help from a pro now could prevent you from filling your manuscript with pernicious errors that will inflate your editing rate down the line. (Incorrect use of dialogue tags and action beats, I’m looking at you!)
Before you’re ready for professional editing
Once you sense you’re nearing the limits of your ability to improve your book on your own, it’s time to bring in beta readers. Beta readers provide high-level, subjective, personal feedback such as “the pacing felt slow in the middle” or “I just didn’t like that character at all.”
Although paying for beta reading ensures the readers will finish the book and return feedback, it’s not necessary to hire a pro. In fact (unpopular opinion ahead), an editor is the wrong choice for beta reading. The reason is simple: Beta reading is not Editing Lite™. It’s designed to generate genuine reader reaction, not analysis from a trained professional.
When you’re ready for professional editing
When you’re ready for professional editing, marching in with a request for a particular type or level of editing puts you at risk of getting precisely what you ask for—whether your manuscript needs it or not. It would be like relying on Dr. Google to diagnose a physical ailment, then convincing a local doctor to prescribe strictly the medications and treatments you’ve decided you need.
Choose your editor with care. You deserve a specialist who resonates with you and your work, not whoever offers the lowest rates and immediate availability.
Once you’ve found the perfect editorial collaborator, let them recommend what your manuscript needs. Their recommendations should be based on what will best support your story, your writing, and your publishing goals. If your editor hasn’t reviewed all those points, you can’t be sure you’ll get what you need.
Link to the rest at Writers Helping Writers
Writers do these things differently: some actually self-edit with success, then run their stuff past an experienced reader of some kind – and then it’s finished.
It depends.
While some input can be helpful, a lot of input (as described here) can be downright devastating, causing the book to lose and alter the voice of the author. In my opinion, it may be better to first publish the book when the author is done and line editing is done. Then get the results from readers who buy the book. Filter those too, since subjective advice is often dependent on the personal tastes of the reader. If that advice is helpful, use for the next book instead of reinventing the published one.
I am in total agreement with you. Your book should reflect your writing and voice, not that of a committee. I’ve seen too many people give authoritative advice that was their well meant opinion, and that might be fine for another book, but not for the book being reviewed. That said, novice writers generally do need some feedback, but find critique partners in the same genre who are accomplished writers.