It would depend on the risk and reward of any trade and the probabilities associated with the risk reward outcomes. You shouldn't determine risk until you assess the probaility of the risk, the reward and the probability of the reward.
At the same time, only risk what will not screw you up if you lose it. If you were hit with the one in a million loss and you were psychologically screwed up then it wasn't appropriate.
At the same time, only risk what will not screw you up if you lose it. If you were hit with the one in a million loss and you were psychologically screwed up then it wasn't appropriate.