Writing is not like riding a bike.
Writing is like body building.
If you let the discipline drop for too long, all that hard-earned muscle turns to fat.
And not in a good way.
I'm not sure that's the best analogy, either, though. I spent far too much of the last few months unable to assemble a coherent paragraph, but when everything finally clicked, I was, if not at the top of my game, a good ways up the slope.
Still, I plan to keep writing on a regular basis after this paper's done. Work on some freelance RPG projects; script my Magnum Opus Web Comic; at the very least, try to get one decent-sized LJ post in every other day.