> Can anyone elaborate on what Carmack is suggesting here? To specialise in some tool early in your career? Or something else? I think he is overall suggesting

> Can anyone elaborate on what Carmack is suggesting here? To specialise in some tool early in your career? Or something else? I think he is overall suggesting that you should find your business value - your value as an employee to the business you work for. He seems to be specifically talking about "career advice", as advice for employment, so slightly outside of his own experience. He is suggesting a shortcut to this business value is to know one tool deeply enough that you become the go-to person for that tool in your company (whether or not that is in your job description).