Warren Buffett says

“Diversification is protection against ignorance. It makes little sense if you know what you are doing.”

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“Any business plan won’t survive its first encounter with reality. The reality will always be different. It will never be the plan.”

“We both insist on a lot of time being available almost every day to just sit and think. That is very uncommon in American business. We read and think. So Warren and I do more reading and thinking and less doing than most people in business.”