I am new to HOD and will be starting Preparing soon, too, so have been wondering the same thing. When I've looked through the guide, it seems I will need a composition book with lines at times, another with half lines half blank, and also a blank composition book (no lines)...and all of these for one subject! It's a bit confusing!
For instance....Science Exploration suggests an unlined notebook (though they are to write in cursive on no lines???), then there is the science lab sheet (which seems easier to use than making their own each time). Then there is the the History Notebook for the drawing/painting, as well as cursive writing on some days. (Do you use one for drawings and another for the the handwriting/copywork or do you use the same notebook?) Then there is the Common Place book. For Language Arts, I'm figuring on a R&S Notebook, a notebook for the creative writing/poetry assignments, and a separate one still for Dictation. Then, still another one for written narrations and vocabulary. If I'm adding these up correctly, that is 10 or 11 notebooks, or am I supposed to be combining some of these assignments. I did go out and purchase the composition books very inexpensively and like the look of them (because they are easily decorated for each subject), but have still been somewhat unsure if I'm figuring all of the notebooks right.
Would love to hear what others have done, especially if you have NOT used a 3-ring binder with dividers (since we weren't going to do that - though may reconsider if it does seem to be the best way!)