Adrian Savage’s Slow Leadership blog has a thought-provoking post on time:
Every significant project, in any organization, will be late, over budget or riddled with defects, blockages and unexpected mistakes—probably all of these. The more people rush at the last moment, or add extra members to the team who have no idea what's gone on before, the more mistakes, setbacks and snafus they'll create. Initial project time scales and budgets should be treated as no more than guesses fueled by over-optimism and ignorance. Whatever the deadline and estimated cost, mentally double it. Then don't get excited until you've passed that figure. Life is uncertain and Murphy's Law is found everywhere.