I rarely feel an urge to write about things I fully comprehend. More often than not, such regurgitation feels like a chore. I might do it to spread awareness on an issue, but rarely for its own sake.
Instead, I find it more exciting to write about things I don’t yet fully understand, where new information has become available or where I want to clarify my thinking. In other words, to “write so that I know what I think,” or to “write what I need to know.”