If it's just writing to a file or the screen you don't need much. But then you need interpolation of arguments. And other appenders, what about logging to the

If it's just writing to a file or the screen you don't need much. But then you need interpolation of arguments. And other appenders, what about logging to the network for aggregation elsewhere. And logging levels. And a couple more features and corner cases. And before you know it, you're writing a lot of code which could be packaged into a library. But you don't need to, like with most library stuff you could write it in-house yourself.