Recurrence and non-linear arrangement may appear to be separate features, but they work together. Recurrence brings a known truth back to attention; variety in arrangement connects that truth with new subjects and circumstances. A listener encounters the same subject with different implications.
Instruction meets a need for new knowledge, reminder may meet the needs of the informed, and variation in arrangement opens fresh perspectives for both. These are not merely stylistic tricks but methods related to guidance.
Integrated principle: when explaining a recurrence or arrangement, consider the audience, the theme, and what the new setting adds.