It's not a competency if you don't know the edge of it.

You need to have a passionate interest in why things are happening. That cast of mind, kept over long periods, gradually improves your ability to focus on reality. If you don't have the cast of mind, you're destined for failure even if you have a high I.Q.

Black-Scholes works for short-term options, but if it's a long-term option and you think you know something [about the underlying asset], it's insane to use Black-Scholes.

The best armor of old age is a well-spent life preceding it.

It's a good habit to trumpet your failures and be quiet about your successes.

...by regularly reading business newspaper and magazines I am exposed to an enormous amount of material at the micro level.. I find that what I see going on there pretty much informs me about what's happening at the macro level.

Berkshire has the lowest turnover of any major company in the U.S.The Walton family owns more of Wal-Mart than Buffett owns of Berkshire, so it isn't because of large holdings. It's because we have a really unusual shareholder body that thinks of itself as owners and not holders of little pieces of paper.