By combining PHP logs and symfony logs, you can monitor and debug your application easily. During development, the debug mode, the exceptions, and the web debug toolbar help you locate problems. You can even insert custom messages in the log files or in the toolbar for easier debugging.
The command-line interface provides a large number of tools that facilitate the management of your applications, during development and production phases. Among others, the data population, freeze, and synchronization tasks are great time-savers.