(With apologies to Dudley Leavitt)
This may sound a bit clichéd, but as I get older I really do find I know myself better. This is probably in part because every day teaches us something about ourselves and in part because as we get older our personalities stabilise. We gain in experience and we become more knowable. We both begin to penetrate some of our inner mysteries and become less mysterious. This goes for our selves as scholars, too, of course.
I was thinking about this recently when enjoying my annual bout of spring euphoria. Copenhagen is further to the north than the city I grew up in, so the summer days are longer, and the winter nights too. Since moving here, twenty years ago, along with all the other changes one goes through over so many years, I seem to have settled into an annual rhythm characterised by a somewhat melancholy winter, letting up when the light comes back in the spring. The thing is that it's only been recently that I've truly experienced this, as it is happening, as a kind of natural cycle. Something I expect.
We don't think the weather is damaged or broken in the winter, when days get shorter and the air gets colder. We just say it is winter. We don't think of spring as some sort miraculous and permanent return of life. We just recognize the seasons for what they are. But we sometimes forget this about ourselves, imagining that a current nadir or apex of mood is somehow fundamental, indicative of who we "really are".
I hope it won't be controversial to say that individuals will differ here, as will groups. I seem to have recognisable annual cycle of moods, some of which is determined by geography some by idiosyncrasy. Others, of course, have a monthly one, conditioned in part by gender and, again, in part by plain individual quirk. (Just because something is natural doesn't mean it affects everyone equally.) And then there's the whole changing arc of life events—marriage, children, divorce, grandchildren, retirement. We have to let these natural processes have some explanatory power with regard to our ability to get work done and derive satisfaction from it. We have to take them into account. As a culture we understand all this; as individuals we sometimes forget.
One reason to plan your writing process is that it gives you a way of experiencing how your naturally changing moods affect your ability to work. It lets you anticipate times when your work will go slowly and painfully, and when it will proceed easily. It will keep you from drawing too dramatic conclusions from how things are going right now. See your planning and journaling as a kind of "almanac" of your scholarship, a document of your experience. Know when to sow and when to reap, if you will. Know when you should not make major life decisions, because your optimism is likely to be unhinged, and when you should not expect to submit a paper, because your confidence is likely to be lacking.
One last thing. This winter I was less disciplined than usual, which showed me something important. Natural cycles can be tempered by personal habits. If, as the winter darkness approaches, you begin to live less healthily—you exercise less, say, and drink more—this will of course exacerbate the problem. Obviously, you have to be less ambitious at times when you have less energy, but it can be a good idea to be as, let's say, deliberate about what you are doing. Physical health helps you face the changes better. It also makes the euphoria of spring less, let's say, disruptive.