>> "The gist of why estimates are hard: every new piece of software is a machine that has never been built before." What is not explicitly said here is that a

>> "The gist of why estimates are hard: every new piece of software is a machine that has never been built before." What is not explicitly said here is that a good developer needs to know what would be a "new" piece of software. He should be at least vaguely aware of what has been built already, what is within the reach of the state of the art, etc. And just like in the stock market, it is impossibly hard to know all the needed information to come up with wise judgement, complicating the estimation process even more. Yet, this is an essential piece in estimation anyways. Just for example, for some projects you may simply declare them to be beyond the state of the art.