in reply to When to use logging and why?

One of the greatest reasons to use logging is so that whenever your customers start telling you that your application isn't working right, you can determine what happened and tell them "Yes it is, you just were not using it right."

Logging is great any time you as a programmer want to know what the program is doing when somebody else is using it. Because if you rely on the somebody else, the message is sure to be lost in the translation.