Check the motive before the move. Good actions for bad reasons tend to rot.

An action can come from generosity or from an expectation of return, and in the moment the two are hard to tell apart. The difference surfaces later, in whether you keep score. Kindness done for what it will earn turns into resentment when the payment does not arrive, and the other person never knew they had a debt.

Before the next favor, ask plainly what you hope comes back. If the honest answer is something specific, either ask for it directly or let the favor go. Either one is cleaner than the version where you wait.