[lfischer]

Often logging libraries allow you changing the logging level at runtime, without restarting or recompiling the application, as well as turning logs or off at runtime for different parts of the application. They let you organize logging levels so that when, for example, you turn the level to INFO in one part of the applications, all of the connected code also gets its own log level turned to INFO and you can define which parts of the application should change their log levels in sync. There's also performance considerations, often log libraries claim to implement tricks so that logging is supposed to be faster than naively writing strings to a file.