This is the most famous claim from Outliers. Malcolm Gladwell uses Bill Gates and the Beatles to support his claim that “about 10,000 hours” are required to develop a skill such that you’ll truly become an outlier in that field. The Beatles played 7+ straight hour shows 200+ nights a year for multiple years. This forced them to grow and develop beyond just playing their ‘best songs’. Bill Gates spent his childhood taking advantage of an opportunity to code on a computer for free. Over the course of their early careers they all logged 10,000 hours.
10,000 hours is about 3 hours a day every day for 10 years. Or 5 years of 40 hours/week.