I think that depends on the writer. Some writers claim to work out the entire story in their heads before they writer, but I've never been able to do that. In fact, I don't even outline. I'm one of those just-start-writing writers. But that's not to say I don't encounter problems. I've spent weeks on a single paragraph.
Beneath a Buried House
http://www.amazon.com/dp/B003SE7J6I