Recipe collections are aspirational. The real cooking in a house comes from a short, unwritten rotation that everyone can make and nobody has ever recorded, because why would you write down the thing you make every Tuesday.
Because somebody else cannot make it
The rotation lives in one or two people's hands. Which means when they are away, sick, or just done, dinner reverts to takeout — not from lack of willingness but because the knowledge was never externalized. A written version of the nine meals is the most-used document a kitchen can have.
And it makes the shopping list mechanical
Once the rotation is written, a week's plan produces its own grocery list. That is the actual payoff: not culinary ambition, but removing the Sunday-evening act of reconstructing from memory what seven dinners require.