I'm going to try tracking exactly for a while, to see if my recollection of "it doesn't vary much" is still correct. But if I sit down and refuse to let my attention wander off and do something else, I will invariably start writing in preference to being bored. Being bored is always worse than writing. n_n But I am also much less critical of my own writing than a lot of writers, so I am less likely to tear up something I wrote as boring or whatever.