I have gotten so used to deadlines that are never met, that whenever anyone tells me that something will take x time to complete, in my head I always estimate that it will be at least 1.5x or 2x.
The strange thing I find is that while human beings are terrible estimators, we are all pretty bad at knowing that we are terrible estimators.
Few economists predict economic crashes, and yet after the fact they write large tomes on why it happened.
The issue is that we never bother accounting for those unknown unknowns, they things that you didn’t even consider considering.
How to fight this tendency? When it comes to timelines, become a hardline pessimist – hope for the best, prepare for the worst.