How should I budget a built-in outdoor kitchen before the patio is poured?

Treat the spare conduit as a defined item on the utility plan, not just “future use.” Label the accessible termination and intended use, whether that is a particular low-voltage cable category or a permitted line-voltage circuit.

The conduit should be sized and detailed for that use, with the required fittings and sealed ends. Keep low-voltage and power pathways separate, and place the termination outside the refrigerator, trash pullout, and masonry zones. A note identifying the maximum intended cable or circuit type can keep a future installer from assuming the conduit supports more than it was designed for.