I have often read on the internet that one needs 10,000 hours ( Malcolm Gladwell's Theory ) of deliberate practice to become good at something. It takes about 7 years @ 4 hours per day. Does this mean that is someone can devote 8 hrs. per day for that activity ( say programming ) then s/he can become expert in it within 3.5 years ? Also, if a person spends one hour per day practicing ( say music ), then is he likely to get more expertise within the same 10,000 hours than a person who reaches those 10,000 hours within 3.5 /4 years ?
Also, does this 10,000 hours rule holds valid for a particular activity or a complete field? For example, if a person wants to become proficient in mathematics, then does he need to spend 10k hrs on every branch of mathematics OR 10K hrs. on mathematics as whole.