How much is it worth?

The cost of a thing is the amount of what I will call life which is required to be exchanged for it, immediately or in the long run.

As you grow accustomed to giving bare attention to sound simply as sound, you'll find yourself able to listen to criticism without becoming angry or defensive and able to listen to praise without becoming overly proud or excited. You can simply listen to what other people say with a much more relaxed and balanced attitude, without being carried away by an emotional response.