In asp.net 3.5, is it valid to throw an exception for invalid arguments, for example? I disagree with this since the caller isn't going to do anything special with the exception. So why throw it? I say if you aren't going to handle the exception then let your friendly formatted errorpage.aspx report it. I'd like to hear arguments for against throwing exceptions. I'm not sure why someone would want to throw an exception just to report a problem.