Prefect's journey to achieving type completeness in their codebase was initiated by a GitHub discussion highlighting the lack of comprehensive type annotations, which are essential for maintaining code integrity and enhancing user experience. Despite initial assumptions that completing the remaining third of type annotations would be straightforward, the process revealed unforeseen challenges and complexities. This initiative demonstrated the multifaceted benefits of type annotations, such as providing safety in Python's flexible aspects, improving developer experience through better IDE support, and enhancing documentation reliability. Additionally, type annotations play a crucial role in scaling a codebase, facilitating collaboration among developers, and aiding AI tools in generating accurate and meaningful code. Prefect's commitment to type completeness has not only fortified their codebase but also underscored the importance of trust in software development, enabling more reliable, maintainable, and accessible systems.