That’s a great question! A good way to know if your book is ready for proofreading is when you’ve completed all major edits—plot, structure, and character development. Before sending it off, try reading it aloud or doing a focused reading passage review to catch awkward phrasing or inconsistencies. If everything flows smoothly and you’re no longer making big content changes, it’s time for a proofreader to polish grammar, punctuation, and style details. A clear, finalized draft makes the proofreading process much more effective.