Granted, I teach 5th graders so take whatever I say with a grain of salt with 11th graders. This book about writer's notebooks really helped see the benefit of having one. This focuses more on having a free space to write whatever they want that can snowball into a larger idea.
I say grading or looking through them every 2 weeks or so should be good but I think checking them may be hard if they're using it for notes or planning. Perhaps having a multi subject notebook or a writers notebook and a binder for notes and such could help with all the uses you want from it?
Sorry this was a little scattered (#onemoreweekofschool) but let me know if you have any questions!
My first year too and I’m fourth. We are reading this and they get their own writers notebook with unlined paper to brainstorm (these are just white paper with a color card stock as the cover). I didn’t come up with this idea, a veteran teacher has helped me so sharing with you.
https://www.amazon.com/Writers-Notebook-Unlocking-Writer-Within/dp/0380784300
Also, heart maps. When they need an idea of what to write about they can reference their heart map.
https://www.wsra.org/assets/Convention/Handouts_2013/a6%20georgia%20heard%20heart%20mapping.pdf