matociquala has
an insightful post here on her discovery--after years of successful books and met deadlines--that the butt-in-chair, eight-hours-a-day make-that-deadline pressure is not good for her, though many of her peers think that's the way you do it.
I know some will look at that and think, hoo, I wish someone was giving me a deadline. If you look past that (and I know it's tough when you wait month after month--year after year--for zippo response on your sub) and see how one's "professional approach" is another's sure-fire recipe for depression, it proves that not all writers write the same way, or on the same timetable.
She's able to pull it off and keep her quality high, but at what cost? Meanwhile, if you've begun reading a series in which the first book is spifferoo but the ones that come out with gratifying rapidily right after (which is good, right? because you're hooked?) seem to go downhill, the chances are pretty good that the writer is not a lazy no-talent, but might have gotten bedazzled into agreeing to tight pub dates that don't take into account how long it took to write that first book.
A thing to keep in mind for when that wonderful call does come--"Hello, I want to buy your series."