10,000
Malcolm Gladwell in his book “Outliers” reported studies that it takes about 10,000 hours for any person to become an expert based on studies conducted in various laboratories. This is a big number. Consider an 8 hour day with a 40 hour week specializing in only one area. With 50 weeks that equates to about 2000 hours per year which infers to about 5 years to become an expert? Curiously, that is the length of average PhD! This amount of time is required to become an expert in any one area. Assuming that is absolutely true for many people that learn a profession, that would be the time for education. However, it is entirely likely that this would be different at different ages and probably much easier at an younger age.
100,000
Individual chunks of knowledge require becoming an expert as summarized in Ray Kurzweil’s book “How to create a mind”. One of the areas from where this was derived is comparing the strategy employed by human vs. computers while playing chess. Gary Kasparov has been assumed to learn about 100,000 board positions. Shakespeare composed his plays with 100,000 word senses, using about 29,000 words and medical specialist similarly learns about 100,000 concepts. It is possible that this amassing of knowledge takes the 10,000 hours that is required to program the brain.