Dear Miss Snark:
I've just fulfilled a two book deal at my long term publisher. I've already outlined my next novel (which is more commercial than my previous six). Usually, I would submit the outline to my editor, she'd make an offer and my agent and I would accept it. My last three advances have been for roughly the same amount. My sales haven't grown exponentially. They climb steadily book by book. I've earned royalties on three out of four (of the remaining two books, one is just out, and one comes out next year).
What to do? I could submit my new outline to my usual editor NOW and go with her predictable (decent) advance. Or I could I write the entire book first and send it to the handful of editors who have expressed interest in me in the past, and might be in the position to offer more (or nothing). I'd be writing without a net, as it were. I'd dearly miss the income. My agent is excellent at seeing the pros and cons of both scenarios, and not so good at definitive advice. How would you advise one of your writers? Go for the risk, or play it safe?
As an established author with a decent track record you don't have to write the entire novel to sell it. You really don't have to write it for your agent to get an idea if anyone is seriously interested in coughing up dough. Particularly if this is a "more commercial" novel, I'd be champing at the bit to move to a place with better money. Higher risks of course..you fall on your ass here and you're REALLY going to miss the income cause you won't have book next anywhere in this town.
Much of this depends on the specifics of numbers, and type of book. If you fall flat on your ass, your agent does too, so risk-averse choices sound mighty good some days.
I think someone once said "faint hearts ne'er won a fair maiden" but maybe you don't want to win a maiden-I hear the upkeep is a bitch.