There&#x27;s also feature creep, which is a pretty big problem in a lot of less organised companies and organisations.  The original design may well be a six page website with mostly static content, but the final version could just as easily be a web app with a built in help&#x2F;support&#x2F;ticket&#x2F;chat system, member accounts and live updating from a third party API.  One two week estimate easily becomes a six months one.<p>Or it&#x27;s delayed because of more and more edge cases being found and someone not wanting to be consistent about them.  If the first, third, ninth, sixty second and hundredth items in a loop have to all act differently for seemingly random reasons, that adds a lot of time to the development.<p>It unfortunately doesn&#x27;t matter how good your estimate is if the company&#x2F;client tosses out the orignal spec at the first possible opportunity.<p>But for well managed projects, yeah, it&#x27;s a good writeup.