Usually, you keep an ink pen, as I suggested, and ink is really a solid thing, because it’s a classic. It makes you feel more classic. And also, the felt-tip pens.. if you’re a serious writer and you’ll be selling your manuscripts to libraries and museums in twenty years, remember that felt-tip pens eat through the page in ten years. So if you want your immortal original manuscripts to be preserved, don’t use a felt-tip pen, which has acid in it. Ball-point tends to scratch into the page and begin the page’s decay. So a regular old-fashioned (fountain) pen, with unwashable ink, is actually about the best, particularly if you’ve got your notebook in your knapsack and you’re fording a stream! - In other words, if you’re writing, take it seriously enough to make a sacred ink out of it, and get some good materials, so it’ll be solid for you. However the danger of having too good a notebook is (that) you’ll get afraid to write in it. So it’s good to vary that. After you’ve filled one really good notebook, get a cheap school copybook which you don’t have to write immortal works in, and those usually produce the best poems! If you’ve had enough practice running through several notebooks, then it might not make any difference what kind of notebook you use. You can write down whatever you want in any notebook. One good principle is not to scratch out anything you’ve written but go on and write something else instead (not as an absolute rule, but as a general tendency), like, don’t depend on another minute or another hour for the completion of your thought-emotion, because if anything’s there, it’ll be there right now when you’re writing. So there’s really, in some sense, no need to scratch out, once your mind is focused (but that requires, then, revising your mind).