When do you actually have a book worth writing?
When is it time to reach out to an editor?
When are you ready to "hand it off" for "next steps"?
The truth is that there are a thousand iterations of your book that could be right, and none of the evaluative tools or rubrics in the world can tell you if you've landed on the right one for you, in this stage of your life, in this moment in time.
And that's both good and bad news.
Bad news because I can't tell you—now or ever—if your book is publishable just by looking at it. Good news because we can figure it out together.
I know none of that is really helpful, and probably sounds a lot like a ploy to get you on my calendar. It is true, but let me take a stab at a more helpful set of answers:
When do you have a book worth writing? When you try to stop writing it but the ideas keep coming anyway. Caveat: That doesn't mean a pause in ideas tells you the book is trash. Sometimes we need to let something good sit for a while to get better. See also: whiskey.
Double caveat: going into discovery doesn't always mean we discover a book. It's absolutely valid to spend two- to four-hours digging into your aspirations both as an author as not, the profile of the audience you're trying to move, and the summary of the direction you want to move them in...only to find out that another medium is better for that particular combination of factors. This is why I always start with a discovery, and why I ask even before that call "why a book?" Because a much better question than "is my book worth writing?" is "what's the best way to deliver this message?"
When is it time to reach out to an editor? Development editors like me are a good choice any time you feel stuck. I tell my homeschooled kids to call for me if they've been staring at a blank screen for ten minutes. Book-writing allots for a bit slower pace than that, but if you're beating your head against a stack of craft books, it's time to put down the obligations and pick up a time on someone's calendar.
Line editors step in when the manuscript has what you want to say in the order you want to say it—they edit a bit more deeply to make sure you're saying it in the strongest way possible.
Copy editors are a go when you're happy with the phrasing and need an eye on errors, consistency, and minor clarity. Proofreading is for a pretty clean manuscript that just needs another set of eyes—sometimes after the layout is designed.
Note: I currently apply half of my eval fees as a deposit on editing if you want to move ahead with me or one of my referrals. When we've got a jump on the work, the edit is efficient enough to make that kind of wiggle room. Plus I love bringing my friends good clients and great work.
When are you ready to "hand it off" for "next steps"? A similar answer goes here, but with the note that this kind of language is common...and way too dramatic, in my opinion. I get wanting to be done with the thing. There's definitely a time for washing your hands of it and letting someone else take the reins.
I don't believe you can outsource the knowing, but I do think we can name some specific things to help you feel more confident in your decision to revise more or call it done.
And I absolutely believe you don't have to hold any part of that process alone.