In addition to using binders, we also use a special binding tool to create individual notebooks for some topics and purposes. There are a variety of these tools available on the market both online and at your local office supply store. My favorite (so far) has been the ProClick Binding Machine.
This hand-operated tool zips holes all along the edge of your paper. Then you simply insert the flexible spine and zip it closed with the little plastic zipping tool. So easy to use! They easily zip open and close making them perfect for growing notebooks. You can create your own sketchbook, planner, journal, or other type of notebook. You can also snip the spines to make smaller size notebooks like my kids' quiet time journals pictured below.
We absolutely love this tool! In fact, my husband purchased his own to create presentation booklets for his clients.
I purchased our ProClick tool many years ago from Amazon.com. This seems to be the best place to purchase the punching tool. However, it's nearly double the price it was 10-12 years ago.
Here are some samples of projects we've created with ProClick...
The kids created their own mini-notebooks for their Quiet Times & Prayer Lists:
These are homeschool assignment / daily record books we created: