A manual for writers of research papers, theses, and dissertations, Ninth edition - Kate L. Turabian 2018

File away leftovers
Planning a first draft
Research and writing

Once you have a plan, you may discover that you have a lot of material left over that doesn’t fit into it. Resist the impulse to shoehorn these leftovers into your paper just to show your work. In fact, if you don’t have more leftovers than what you used, you may not have done enough research. Leftovers aren’t waste: at a minimum, they helped you discover your ideas. You might decide that you need to use them after all. And they could even contain the seeds of another project.