What do you mean 'we need more time'??
Project Schedule Estimation in Software Development
"How long will it take?" Even if you’re uber-Agile and don’t believe in far-off project deadlines, rest assured that somebody will crack under the pressure and give a date, which your team will be held to. When that date hits and you are not ready to launch, your manager will be angry at you because you made her look like a fool, sales will be angry at you because they promised your most important customers that they could have it today, and your team will be angry at you because they’ve worked five weekends in a row trying to hit an impossible deadline. So let’s just dodge that whole mess and create a schedule that you can live up to.
Bland det bästa jag har läst på länge om utveckling och tidsuppskattning. Hela artikeln bör läsas av både utvecklare och beställare.
Från Dropbox tech-blog.