&gt; It&#x27;s not a bad thing to do a lot of estimating up front so the business can make an informed decision about whether it really wants to commit to the effort...<p>You&#x27;re assuming the estimate is worth much. Which is what much of the industry is doubtful about. To underscore the point, most estimates are single values (eight months), not confidence intervals.<p>A better answer would be, &quot;There is a 50% chance that we get it done between six and seven months from now, assuming requirements don&#x27;t change.&quot;<p>...but even that assumes that all along the way, the project stakeholders are keeping in mind how many (how do you quantify?) requirements were added and discovered.