I’m not entirely sure where the best places are to insert orbit review areas in the piece. Should I have one question every few paragraphs? Or have a few of them lumped together after a major section? You’ll see that I’ve tried both in this piece.
This is an important question!
I think the right answer is mostly a function of the density of new ideas in the text. At a high level, I’d suggest you want a review area whenever you’ve introduced enough new terms, concepts, etc that the reader’s working memory is likely overflowing.
This gets easier as you get better at writing good questions. That’s because you can approach this by diligently writing questions modeling all the key ideas you’re introducing, then noticing when a single review area has 10+ questions in it. That’s a good sign that it’d be helpful to intersperse the review areas more regularly, since 10+ new ideas is likely to overload the reader’s working memory.
Another angle on this is to think in terms of the structure of the piece, relative to effort and rest points. These review areas offer a respite from new information; they feel like a “save point.” The cadence of the piece may naturally suggest places where that will feel appropriate.