An important factor to note is that it's rare for anyone to sell a first novel written before they turned 30-35; long-format fiction tends to require a bunch of experience of human life that takes time to acquire. So your average mid-career novelist is in their forties to fifties!
Charles StrossI drink tea pretty much continuously at a rate of around 1 imperial pint/hour, which sort of enforces screen/keyboard breaks.
Charles StrossTime is a corrosive fluid, dissolving motivation, destroying novelty, and leaching the joy from life.
Charles Stross