Quit Every 3 Years - by Chris Anderson

"When I was at The Economist, there was a policy to rotate everyone every three years. The idea was that fresh eyes were more important than experience.

I was thinking about the three-year rule while reading about Malcolm Gladwell's observation that it takes 10,000 hours to become truly expert at something. If you really throw yourself into a job, you'll spend 60 hours a week working. That's 3,000 hours a year (allowing for vacation), which means you'll hit the 10,000 hour mark a few months after your third year.

So maybe that's where the three-year rule comes from. You're now expert at what you set out to master. Great. Now go do something else."

http://www.longtail.com/the_long_tail/2008/12/do-something-ne.html
http://www.longtail.com/the_long_tail/2008/12/do-something-ne.html