On competence.................

Understanding the limits of your own competence is very valuable.  Venture capitalist Fred Wilson put it simply:  "The only way you win is by knowing what you're good at and what you're not good at, and sticking to what you're good at."  Munger similarly believes that investors who get outside of what he calls their circle of competence can easily find themselves in big trouble. . . .
    The idea behind the circle of competence is so simple that it is arguably embarrassing to say it out loud:  when you do not know what you're doing, it is riskier than when you do know what you're doing.  What could be simpler?

-Tren Griffin,   Charlie Munger:  The Complete Investor