I just finished writing my third novel, a book I started quite a while ago, and I'm having a hard time disengaging from the characters and moving on to the next book. Their voices have been inside my head for so long that I'm having separation anxiety, a feeling somewhere between loneliness and multiple personality disorder. (Yes, writers do hear voices – scraps of dialog colliding somewhere in your hippocampus. I've always believed that good writers are neurotic and great writers are schizophrenic.)
Anyway, the book's narrative weaves together the lives of ten people who would normally have nothing in common beyond the fact that they live in the same apartment building. They might say hello in the elevator, as neighbors often do, but they have no real reason to interact until their landlord gets thrown off the roof of the building. Because he was an unrepentant asshole who gave every one of them cause to want him dead, there is suddenly a very good reason for these ten people to get to know each other. And when they do, let's just say mayhem ensues.
But I'm drifting away from the question, which is how writers deal with saying goodbye to characters they've nurtured for so long, clean the attic of their mind and move on. Fortunately I have a deadline that will force the issue, but I'm taking a week or two off from writing to catch up on my reading, maybe hear some new voices in my head like those of my fellow MI writers with new books out.
After that I'll return to the keyboard and see what kind of characters decide to show up on the page. I hope I like them as much as the ones I just stuck in a box and shipped to my agent. We'll see...