There are 56,956 personal finance books on Amazon.com. In aggregate, they contain more than 3 billion words. This seems absurd, because 99% of personal finance can be summarized in nine words: Work a lot, spend a little, invest the difference. Master that, and the other 2.999 billion words are filler.

The most important finance topics don’t require details. Most can be, and should be, summarized in a sentence or two.

Here are some I’ve learned.

1. Dollar-cost average for your entire life and you’ll beat almost everyone who doesn’t.

3. Every five to seven years, people forget that recessions occur every five to seven years.

4. You’re twice as biased as you think you are (four times if you disagree with that statement).

6. Read more history and fewer forecasts.

7. It’s strange that you go to the doctor once a year, but check your investments once a day.

8. When reading about some of the stupid things investors do, don’t forget you’re an investor.

9. Your circle of competence is probably 80% smaller than you think it is.

10. You’re only diversified when some of your investments perform worse than others.

13. When in doubt, choose the investment with the lowest fee.

14. Emotional intelligence is more important than book intelligence.

15. The more you learn about the economy, the more you realize you have no idea what’s going on.

16. Start saving for your retirement before you graduate college. You’ll feel silly when you start and like a genius when you finish.

17. The most powerful way to grow your money is learning to live with less, since you have complete control over it.

20. You have a strict obligation to not have an opinion about things you don’t understand.

22. You shouldn’t feel strongly about any investment you haven’t spent at least a week thinking about.

23. Holding 60% of your assets in stocks and 40% in bonds isn’t perfect for everyone; but I can think of a hundred worse strategies.

24. Respect the role luck has played on some of your role models.

26. Change your mind as often as the facts change.

27. Ignore people who refuse to change theirs when the facts change.

28. Read last year’s market predictions and you’ll never again take this year’s predictions seriously.

31. Two things you can do to make yourself a better investor are think long term, and stay humble.

33. Warren Buffett has the best explanation of dumb risk-taking: “To make money they didn’t need, they risked what they did have and did need. And that’s foolish. It is just plain foolish.”

34. You can probably afford not to be a great investor — you probably can’t afford to be a bad one.

35. You’re twice as gullible as you think you are.

36. Learn more from your bad decisions than your good ones.

37. Judge investors by the quality of their arguments, not the performance of their last trade.

40. Admit when you are wrong, and take satisfaction that you have learned something of value.

41. Imagine how much stuff you’d have to make up if you were forced to talk 24/7. Remember this when watching financial news on TV.

42. There is, and always will be, more money to be made providing investment advice than receiving it.

44. Save for your own retirement; assume Social Security and private pensions won’t be around (even though they probably will).

46. The correlation between confidence and future regret is incredibly high.

47. During the last 100 years, there have been more 10% market pullbacks than Christmases. Everyone knows Christmas will come; think of volatility the same way.

50. Not taking advantage of an employer match on your 401(k) is no different than declining a raise.

51. Don’t let Washington sway your investment decisions. Congress has been a dysfunctional swamp of disappointment since 1789, and stocks have done well ever since.

54. “Invest in what you know” is dangerously oversimplified.

55. Quit day trading, and donate your money to charity instead. Same financial result for you, and a better outcome for society.

57. Reaching for yield to increase your income is like sticking your hands in a fire to warm them up — good in theory, disastrous in practice.

58. Your devotion to a political party or ideology is directly proportional to your tendency to think irrationally about how politics affects your investments.

59. Most people need a financial adviser, but everyone needs a financial counselor, or someone to talk them off the ledge before making a dumb decision.