For long-running projects, I also use A5 notebooks that are pre-partitioned at a given % (I use 60-70%). The idea is that you go over your old notebook with "odd chicken scratchings", count the number of pages spent on each topic, calculate the ratios and multiply them by 70%*NUM_PaGES. Then you allocate this number of pages in the new (clean) notebook and put tab stickers on each section. I also leave around 4 pages for the TOC in the beginning of a notebook. It's just 2 sheets, but the ability to go back and put an extensive TOC later helps a lot when you refer to a finished notebook. With a bit of patience, you can but together a perfectly ordered TOC in a completely messy notebook (by doing one pass over all notes before writing down the TOC and grouping them by project). I also tried keeping notes on paper and writing down the TOC digitally in my Evernote to keep it searchable.
Regarding spiral binding, I find it too flimsy. If you damage the spiral, flipping pages would cause damage to the pages. I prefer hardbound notebooks. I use fountain pens and previously used expensive paper but since the pandemic I tried Idena [2] and it simply blew me away with its high quality and ink resistance (except for some rare inks) at such a low cost (but I had to give up the dot grid).
Ultimately, I am convinced that all of this has a limit and a Zettelkasten method of sorts is needed for a long-running knowledge base project.
[1]: https://www.amazon.de/dp/B004F69CRC [2]: https://www.amazon.de/Idena-209281-Notizbuch-kariert-schwarz...
I'm not sure I'll stay with that, but so far it looks good. I like the thick paper, the wide availability and the low price. I can reorder stuff, I can take single index cards out, and I don't regret throwing cards away.
A few months ago I also looked into a bunch of note taking methods, even bought a similar A5, spiral bound, pre-formatted organizer and thought it'd be perfect for organizing my days. It remains unused except for a couple of lines where I began to note the days tasks, then crossed them out and tried to start again the next day.
But a dot grid purchased around the same time is filling up very quickly with odd chicken scratchings of work notes. The only hint of structure are dates scrawled wherever I happened to be starting from that day. Any very important things get circled or marked with an asterisk