Hiding in drawers are the pages of several never completed manuscripts by yours truly. I've opened those drawers, peeked at the unfinished writings, and sighed as I closed the drawers up again. They have the look of a road ending at a chasm that spirals down into the darkest abyss of authorial hell.
Shelved projects aren't a bad thing. I imagine most authors have one or two (or many)lingering in their own hiding places. As an author grows in their craft, some of those lifeless manuscripts can be resurrected into something great. But if they never do, it's okay to have a few unfinished manuscripts.
Contrary to the above statement, I am always encouraging new writers to persevere with what they've got. Just FINISH it! My advice to writers is for them to just get it done.
Where is the balance between just getting it done and knowing when to shelve?
For me, it's when I'm bored. I'm bored with the characters, the plot, the whole thing. When the book holds no interest for me as the author, I feel safe to assume it will become a new prescription for curing insomnia if I let it out into the public. That is when I print it out, and put it away where no one will find it.
And yet, I still think it's important to finish one book. You cannot make a career of shelving. You have to finish one simply to prove to yourself that you CAN. It's an amazing moment when a writer reaches "the end" of their first book. It's a sacred rite of passage from writer to author. So I don't recommend shelving until you've actually proven you can carry a book to completion.
I maintain that nothing we write is ever wasted. Every verse of terrible poetry and line of absurd dialogue carries us closer to the writers we will someday be. All of my hidden uncompleted work served as my education process. I can look in those drawers and say, "This is where I found my voice, my rhythm, myself."
This post today is because I have a friend with countless uncompleted manuscripts hiding in his secret places. He's never finished a book. He's been at it for eighteen years--long enough to raise a child to adulthood. And I want to scream at him, "Just get it done!!!!!!" (and yes, with that many exclamation points). In fact, I did tell him he needed to stop dabbling and jump in. His response was to remind me that I told him it's okay to shelve products when you know they aren't going anywhere. Oh the agony of being quoted out of context.
It's okay to know when a book isn't going anywhere and it's time to walk away. But if you're finding yourself always walking away, you'll miss the magical moment of completion, that moment when you step from the world of merely writing to the world of actually authoring.
Be picky about what you're writing later. There's lots of time for rewrites. But for now, just get it done!