Occasionally you may run out of room on a page but you’re not done tracking that item. Rather than have multiple entries for the same thing you can use threading!
I haven’t used threading, although I kind of wish I had since my index is getting a little hairy.
Here’s how you use it, on the index I would just list “Habits (8, 35, 41, ” rather than “January Habits 8-9” and “February Habits 35” and so on.
Then at the bottom of my January habits, next to the page number, I would notate which page to continue to when I’m done. This picture is from the last page in my book which I also use for doodling.
You can also use 8 | 35 if you prefer the line over the dot. Remember this journal is just for you so use what you like.