How to know when there's too much logging messages?

I came across one very good library for parsing CUE files. But when I started to read its source code, I realized that it is almost unreadable:

public void setParent(final CueSheet parent) {
    FileData.logger.entering(FileData.class.getCanonicalName(), "setParent(CueSheet)", parent);
    this.parent = parent;
    FileData.logger.exiting(FileData.class.getCanonicalName(), "setParent(CueSheet)");
}

every method has logger.entering() and logger.exiting() messages. Isn't that too much?

There's another java library for parsing audio tags. It also had like 15 log messages for each file it read. It was annoying so I commented out every call to logger. And the library became twice as fast, because they used a lot of string concatenation for log messages.

So the question is: should I really log everything, even if it is not large enterprise application? Because these libraries obviously don't need any logging, except for error messages. And my experience shows that loggers are terrible tool for debugging. Why should I use it?