“Something that everyone knows isn't worth anything.”

Simplified Meaning:

When everybody knows something, it loses value because it's no longer special or unique. Think about a piece of advice that everyone hears all the time, like "drink lots of water." Since everyone knows it, people might start ignoring its importance. But if someone gives you a unique health tip that isn’t widely known, you'll probably find it more valuable and might pay more attention to it. Imagine a secret recipe for a delicious cake. If only a few people know this recipe, they can make and sell cakes that are very special and highly desired. But if the recipe is shared with everyone, the cake stops being special because anybody can make it. In life, we should look for and appreciate unique knowledge or skills that not everyone has. This way, we can stand out and offer something special, whether it's in our career or personal life. To make the most of it, don't just focus on what everyone else knows; try to find and learn things that are rare and valuable.