I absolutely buffer in two different ways. I buffer in terms of actual releases, each chapter being completed and ready well in advance, as well as a buffer time wise. I release my story bi-weekly with at least 4 chapters and about 16-20 files average per batch. Meaning I get at least 8 weeks to plan out, write, storyboard, draft, ink, color and add text to the next batch. If one chapter ends up being too long, I'll cut it in half, giving me another 2 weeks.
I do this purely because I know how much time I have to work on this story a day and need to maximize it, but releasing weekly is way too much pressure. Bi-weekly is easier on the mind, body and heart. At the moment, my next deadline is the end of July, which I am well ahead of. This gives me more breathing room in production for the next batch or extra time I can take off and recover.