> then they need to provide precise requirements > They can do that. Yeah, no, they can't. Not at all. While some, or a lot of that, is due to incompetence,

> then they need to provide precise requirements > They can do that. Yeah, no, they can't. Not at all. While some, or a lot of that, is due to incompetence, it is also due to the nature of the beast: Software Development is an iterative process. You have to prototype and figure out what works and what not. So regardless on how tight your processes are, whether you use agile or waterfall, it will never be possible to give perfect time estimates. You can only improve your risk-management.