They don't. They just gain expertise on subjects through trial-and-error and first-hand experience. Anyone who tries to convince you that your should pay for a

They don't. They just gain expertise on subjects through trial-and-error and first-hand experience. Anyone who tries to convince you that your should pay for advice on "how to become an expert" has expertise at only one thing: lying. PS: I can teach you how to be an expert at spotting liars. For 5 dollars I'll tell you the secret. Behind paywall 1: First lesson - don't pay for lessons on expertise. For 5 more dollars, I'll let you read chapter 2 Behind paywall 2: You are almost there! So close! You should be getting familiar with the trick by now. There was a secret lesson in part one. I'll tell the secret behind the trick for just 5 more dollars. Behind paywall 3: Fool me once, shame on you. Fool me twice, shame on me. Fool me three times, and now we are here! Wanna know how I fooled you three times? Only 5 more dollars! Now you are 15 dollars into spending 5 dollars on how to spot a liar. Just 5 more dollars! Once you figure out the trick, you can consider yourself an expert.