Is expected value all that matters? I have heard of the Kelly criterion but what should you do if you cannot allocate the optimal amount? For example, if you have a 0.01% chance of winning $100,000,000 but a 99.9% chance of losing $10,000 and you could only bet once, would you accept the bet? From a mathematical perspective, if the expected return is positive, as in the case above, should you always take the bet? If not why? How do you determine whether to bet or not from the information above (from a rational, statistical approach).