I am in favor of deadlines, the fiercer the better. All but impossible for preference. I don't really believe in a deadline unless I can see it right in front of me, a rising sun or a rearing thunderclap.
I tell people who want to be writers to draw on the habits and patterns that served them well in any previous line of work. If you have tended to produce best in a structured 9-5 situation, try to establish a similar structure in your writing life. If you generally work best in a group environment, see if you can write with other people or simply among other people, maybe in a nook in the family room.
I functioned pretty well as a journalist for a decade, covering crises in 35 countries. The pattern of my days was to do anything necessary to get the story, write it as well as possible in limited time (often 2,000 words in two hours) and get it in to the office before the publication deadline.
This routine wasn't all that different from life as a student pulling all-nighters to hand in a term paper or even an honors thesis.
It still works for me, but won't produce a book in an all-nighter unless the pieces of the book are all there - produced in previous writing binges - to be streamed together. Don't ask me to be a plodder. Give me a banshee scream in the night that pulls me into action as a fireman slides down the pole to man the engine.
Deadlines give us an edge. A supreme edginess is there in the word, which implies that you are heading for the final line, that this is a matter of life-and-death. I have sometimes wondered about the origin of the word. The etymology, which was given to me overnight by my in-flight reading on a nine-hour flight.*
During the American Civil War, I discovered, the word "deadline" referred to the perimeter around a prison camp, beyond which any errant prisoner or would-be escapee would be shot. I did some more digging and discovered that the term was probably first used at the hellish Andersonville camp maintained by the Confederates for Federal prisoners. An inspection report on Andersonville by a Confederate officer, Captain Walter Bowie, in May 1864 noted:
On the inside of the stockade and twenty feet from it there is a dead-line established, over which no prisoner is allowed to go, day or night, under penalty of being shot.
Now there's an edge. I am not the only writer who has felt that if he fails to get his story in to an editor by the deadline, he will be shot.
* I found this gem in James Geary's wonderful I Is An Other: The Secret Life of Metaphor and How It Shapes the Way We See the World.
Image: The deadline that kept prisoners back from the walls of the stockade was marked by a simple fence. Prisoners who crossed the line were shot by sentries who sat in “pigeon roosts” located every 90 feet along the wall. The man in this image was shot reaching under the fence as he tried to obtain fresher water than was available downstream. (Andersonville National Historic Site)