Mixing both todos and reference material in one place is dangerous: they are different kinds of items and need different processing. Keeping them in one pile will create additional tension as you have to filter through all items each time. The tension is not too bad but with time it leads to you skipping reviews and not doing them the items.
- I have experienced this first-hand. Ability to create todos anywhere is one of org-mode features but I have found that it does not scale well if you start mixing actionable and non-actionable items.
- The same argument is made in Allen2015
If the project is big, I move todos to my main todo file and track them as part of the overall flow/reviews.
If the project is small (e.g., single-file article in org), I keep the tasks in the same file but under a separate “To do” headline.