I've heard it said that all stock traders make losses. They can't tell when that will happen but when it does, it never does come as a surprise [and they cut their losses swiftly before they lose more of their money]. That's probably what scares off most people. If they'll lose the money they'll invest . . . For those new to stock trading, how much do you think they should be prepared to lose while they learn how to trade? 10% of the money they invest? Or maybe a little more?