It is so impossible to trade without any single loss. But the thing is we can compensate every loss thru average down. So do not trade the whole money 100%. Always trade in portion. One more thing do not trade using margin if you dont know how to manage it.
I agree with your answer.I think, Every trader do not trade with all money.All time keep some money for recover their loss.For example few day ago I buy some XVG in 0.00000730 satosi.But few hours later it's rate down and again I buy some xvg in 0.00000700.Then If i sell this coin in 0.00000715 satosi.My loss is recover.