About 40-50% of the time I guess. And presumably another so many percent of projects end up completed long before the deadline instead. Either way, the reasons

About 40-50% of the time I guess. And presumably another so many percent of projects end up completed long before the deadline instead. Either way, the reasons are as follows: 1. The timeframe provided for the project has no correlation to reality, and either under or overestimates the time needed. 2. The client/customer needs to do something... then puts it off a few days/weeks/months. 3. Feature/scope creep kicks in. That's just the work related ones. Personal projects get sidetracked all the time.