Action/Reaction

To every action there is always opposed an equal reaction; or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.
- Newton's Third Law of Motion, translated from the Principia's Latin

Or as Sir  Isaac Newton's Third Law of Motion is most commonly stated, "For every action there is an equal and opposite reaction." Works for cooking. An hour and a half of creating a made-from-scratch pizza  generates 90 minutes of clean-up -- for me. And an hour and a half nap for Charlie.