[synnik]

This may or may not be true... it is an example of the old statement that I learned in martial arts"

There is a vast difference between having 10 years of experience, and having 1 year of experience repeated 10 times.

The reason there are often few differences between a 5-year career and a 10-year career is that most people find a niche after a few years, and comfortably sit there. But if you can find someone who spent 10 year actively learning and broadening their skills, never settling in... those extra 5 years are immensely valuable.