Hedge fund managers use different investment strategies to show how good they are to investors. Good managers make it easy for investors to see their skills, while bad managers make it hard. Investors only give money to hedge funds if they make enough profit. This makes bad managers take big risks to try to make enough profit. As time goes on, bad managers are weeded out, and investors become less strict about how much profit they need. This explains why experienced hedge fund managers don't always make more money, why some hedge funds fail, and why returns are different depending on how long you invest for.