Chemistry, genetics, physics, and linguistics all present instances of reuse. I use the example of how behavioral constraints may have contributed to the emergence of phonemic reuse. Arising from specific facts about speech production, perception, and learning, such constraints suggest that combinatorial reuse is domain-specific. This implies that it would be more prudent to view instances of neural reuse not as reflecting a “fundamental organizational principle,” but as a fortuitous set of converging phenomena.