Most business mistakes are irreversible setbacks, but you get another chance. There are two things in life that you don't get another chance at - marrying the wrong person and what you do with your children.

Never depend on a single source of income.

There are a few investment managers, of course, who are very good - though in the short run, it's difficult to determine whether a great record is due to luck or talent. Most advisors, however, are far better at generating high fees than they are at generating high returns. In truth, their core competence is salesmanship. Rather than listen to their siren songs, investors - large and small - should instead read Jack Bogle's The Little Book of Common Sense Investing.

Derivatives are like sex. It's not who we're sleeping with, it's who they're sleeping with that's the problem.

The most important thing in terms of your circle of competence is not how large the area of it is, but how well you've defined the perimeter.

I don't need 15 houses. Owning real estate doesn't mean much to me. I don't like to think about things like that. I don't need 12 boats, or even the world's largest boat with a crew of 80. I'd have to take care of them, to worry about them. I get a lot more fun out of life without all the bells and whistles.

I have never been able to understand why the tax comes as such a body blow to many people since the rate on long-term capital gain is lower than on most likes of endeavor (tax policy indicated digging ditches is regarded as socially less desirable than shuffling stock certificates).