You open Word and the title of your WiP isn’t listed under “Recent Documents” anymore.
You can’t remember what chapter you’re on.
You have to scroll back to remember the names of some of your minor characters.
You can’t remember what your last scene was about, so...
You have to go back and read several chapters before continuing.
You don’t know the word count of your ms (especially if you’re obsessed about this while writing like I am).
You miss your main characters.
You miss writing.
How do you know it's time?