When are you done writing a novel?

So how do you know when you're *done* writing a novel?<br><br>I've been working on this story for over 10 years. I've rewritten entire chapters and scenes multiple times, added and removed characters and entire arcs, and then I get to the end and then I rewrite everything from page one back.<br><br>I've read books on word choices, I'm halfway through *The Great Gatsby*, and I've been comparing my writing style to my favorite authors.<br><br>I'm about to open a document I made 9 months ago that has every page I've written since then, and I'm wondering, how do you know when you're done writing a novel? <br><br>What should I do?<br><br>TL;DR: How do you know when you're done writing a novel?<br><br>Edit: I've written 150k words.