Circle of competence

Each of us, through experience or study, has built up useful knowledge on certain areas of the world. Some areas are understood by most of us, while some areas require a lot more specialty to evaluate. 

It is important to honestly define what we know and stick to those areas. 

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Charlie Munger once commented that "in order to disagree with somebody you must first understand their argument better than they do."

The most common way people lose money is to overestimate how clever they are and how much they know. Even after a fifty-year investing career, both...

You should search only for helpful information that you can and will apply to your life far more often than you let random information interrupt you.

The Circle of Control is anything that relates directly to you, information that improves how you spend your time.