Power BI development varies based on the type of data source being integrated, whether it's SQL Server, Excel, cloud services like Azure, or third-party applications. SQL Server and Azure offer seamless integration with full query support and optimized refreshes. Integrating with Excel is simpler but may require more manual effort to ensure clean data. Connecting to third-party APIs can introduce complexities, requiring API configuration, data transformation, and error handling. Each data source demands a different development approach to ensure smooth integration and optimal report performance.