For me it can be any notebook, as long as it's spiral bound (to avoid trouble with pages flipping themselves over), lined (to help me write), A5 (to help my car

For me it can be any notebook, as long as it's spiral bound (to avoid trouble with pages flipping themselves over), lined (to help me write), A5 (to help my carry it with me at all times, and write on my lap if necessary) and around 200 pages (to last a reasonable amount of time, but be filled before getting too battered), decent quality, and fairly cheap. Helpfully Amazon (and most stationers) carry "Cambridge Jotter, A5 Notebook, Wirebound, Lined, 200 Page, Pack of 3, green" for £8. I write the date started and finished, and the number on the front and I'm currently on 26/01/2024 #31.