After a horrible experience dealing with Field Notes* I decided to just start making my own mini-notebooks.
If you use printer paper, you can just cut it in half, then trim each half to 7", then take 12 sheets of these 5.5x7" sheets, fold them in half, stack them together, then bind them. The first notebook I made, I used a basic stapler to staple the booklet together which worked fine, but on the second I did a pamphlet stitch which is easy and doesn't have sharp pointy bits in the middle of the book. (all books since have been with this stitch, see note below about saddle stitching)

Go down through the middle hole, come up on the right hole, go over and down through the far left hole, then come up through the center and tie a knot. Have the ends of the string on either side of the middle string you are tying around.
Dimensions I use:
For some future version, I want to use the Axidraw to design some algorithmic covers for each notebook, but really the possibilities for what kind of art you can make for these is limitless.
many notebooks later....

I tried saddle stitching the notebook covers with this video, not sure it's worth the extra work; especially since the normal 3 hole version doesn't fall apart on me or anything. Although if I were to do this again, i'd probably print a guide to make sure the holes are evenly spaced apart. (I might come back and update this section if while using I find that this stitch is amazing for some reason...)
An easy way to start a new notebook, is to first number the inside cover, then open the new notebook on the first page, your previous notebook on the last page, and then travel backwards in your old notebook creating bullet points of all the things you found interesting and important on the first few pages of your new notebook; now the first page of your new notebook is not only not blank, it is covered in the most interesting points to get you moving forward. This is made easier because as I go along, I mark things I find interesting in red pen, so as I'm reviewing an old notebook I can quickly find interesting things.
I do find it strange how I seem to lose momentum when switching from the last page of my old notebook to the first page of the new notebook. Sometimes it even feels like all the stuff I was thinking about in the old notebook is just swept away and I'm starting fresh, even though it's just physically switching from one piece of paper to another. I started the above system to combat this feeling a little bit.
Here is how I got over my sketchbook anxiety (I just stopped using them in favor of loose paper.)
* It seems like the Field Notes brand has finally succumbed to enshittification. On the
last and last time I bought something from them, they automatically signed me up for a Linked(?) account, which is a helpful service
that tracks you around the internet selling all your data to whoever is willing to pay for it. While it only takes a few seconds for them
to setup your account, it takes 6-8 weeks (months? I forget) for them to delete the account I never wanted. This also means if you
were actually ever dumb enough to buy from the field notes website again, they would just sign you up with another account.