So much this. I've written about it before, but one of the big bonuses you get from doing it this way is that it enables you to learn from your mistakes.
A date estimation with no error bars cannot be proven wrong. But! If you say "there's a 50 % chance it's done before this date" then you can look back at your 20 most recent such estimations and around 10 of them better have been on time. Otherwise your estimations are not calibrated. But at least then you know, right? Which you wouldn't without the error bars.
A date estimation with no error bars cannot be proven wrong. But! If you say "there's a 50 % chance it's done before this date" then you can look back at your 20 most recent such estimations and around 10 of them better have been on time. Otherwise your estimations are not calibrated. But at least then you know, right? Which you wouldn't without the error bars.