Suppose that it is true that it takes 10,000 hours to become expert at software development, just like for other arts and skills. Then, if the half life of IT is 10 years, you have to accumulate 5,000 hours of new learning every 10 years. Consequently, you have to devote about 10 hours/week to learning new stuff in order to keep current. If you are lucky in managing your career much of this can be done on the job. Otherwise it must be done on your own time. It is the inability or unwillingness of software developers to devote this much time to continuing learning that accounts for their early obsolescence.
> Suppose that it is true that it takes 10,000 hours to become expert at software development, just like for other arts and skills.
The 10,000 hour rule is just something Gladwell made up on the back of a study which found that people at a certain level in certain fields (classical violin and classical piano) averaged that much experience (EDIT: actually, deliberate practice), while people at lower levels averaged less. It isn't a threshold.
