Why are software development task estimations regularly off by a factor of 2-3?
Excellent analogy by Michael Wolfe on Quora:
We can walk 4 miles per hour for 10 hours per day, so we’ll be there in 10 days. We call our friends and book dinner for next Sunday night. They can’t wait to see us!
We get up early the next day giddy with the excitement of fresh adventure. We strap on our backpacks, whip out our map, and plan day one. We take a look at the map. Uh oh.