To be a successful investor, you should spend most of your time on the companies you actually own. Not on the next idea. Not on the market. On what you already hold. I’m pretty sure that if you took 100 investors who each own 10–15 stocks, 99 of them would fail this simple test. They wouldn't be able to answer basic questions like: 1. What’s the market cap? 2. What’s the trailing and forward P/E (or better, the free cash flow yield)? 3. What did they sell last year, and roughly what will they sell next year? 4. What’s the balance sheet look like, net debt or net cash? How much leverage? 5. How much free cash flow does the business generate, and what do they do with it? If you have made it so far, great, but I promise you at least 90% are out already. Let's continue: 6. How does this business make money, explained simply enough that a smart 12-year-old would get it? 7. Does it have a durable moat? What specifically stops competitors from taking its profits? 8. Tell me about the managment. How are they like individuals? How do they allocate capital? 9. What’s your rough estimate of intrinsic value, and how much margin of safety do you have? 10. What’s the downside? If the thesis is wrong, how much can you permanently lose? 11. How long until the business’s cash flows roughly pay back what you are paying for it? If you can’t answer most of these clearly for every stock you own, you’re not really an owner. You’re a spectator with a brokerage account. The edge in investing doesn’t come from finding more ideas. It comes from knowing the ones you own better than almost everyone else. Most people never do the work. Knowledge of what you own is key for enduring dips (being able to buy cheap) and also know when to sell. If you don't know what you own, then you also don't know its worth. It's true in the opposite direction too. People sometimes take profit too early.