Others above me have mentioned the reasons why they need them. But I'll reiterate my emphasis on rough/relative timelines. Exact dates are impossible and the fa

Others above me have mentioned the reasons why they need them. But I'll reiterate my emphasis on rough/relative timelines. Exact dates are impossible and the farther away a milestone is, the hazier the date is. As an example, a milestone a month away could be +/- a week, but a milestone a year away could be +/- three months.