Here it is:
A two-hour writing session (I mean a serious session, no goofing around on the internet, but two hours of straight concentration and actual work) is as mentally taxing as taking a standardized test for two hours.
It’s as taxing as doing your taxes for two hours.
Meaning: after two hours, you are mentally drained.
Weirdly, I do not find this to be the case for other kinds of art. I can paint for two hours and I feel fine. I don’t think musicians are totally drained after two hours of playing the guitar.
Maybe two hours of trying to learn something NEW at the easel, or at the keyboard, would be exhausting. But the daily habit of making art? In my life, only writing takes such a toll.
The good news about this is that, after twenty years as a professional writer, I have figured this out about myself and I STOP after a couple of hours. I give it all my attention, all my focus, all my effort. I lock the door, I stay off the internet, I do the work. I write my pages.
But–when those couple of hours are over (or, more accurately, when those 1000 words are written, it just happens to take a couple of hours, more or less), I’m done. I don’t have another hour in me, so there’s no point in staring at the screen and trying to make it happen.
Now I plan my day around this. I give my writing the best few hours of the day (which, for me, is in the afternoon, after lunch) and for the rest of the day, I live my life. I go to the gym, I paint, I take care of some business-y tasks, maybe I do some research–but I don’t feel guilty about not putting in more time.
It helps that I don’t think of this as MY limit. I think of it as THE limit. It’s just a fact. Two hours = standardized test = you’re done for the day.