from typing import Optional


def validate_economic_lifetime(economic_lifetime: Optional[int]) -> Optional[int]:
    """
    Validates the economic lifetime of an object.
    Economic lifetime is always optional.

    :param economic_lifetime: The economic lifetime of the object.
    :return: The validated economic lifetime.
    """
    if economic_lifetime is None:
        # Skip validation if no value provided
        return None

    if economic_lifetime <= 0:
        raise ValueError("Economic lifetime must be positive.")

    return economic_lifetime