Don't quit investment if your investment is going good but quit investment if your investment doesn't profit you. Quitting doesn't mean you are loser but sometimes but sometimes it is the most excellent thing to do. It is depends on the result and not depends on just nothing to produce profit.
That's being practical, why would you continue if you are not making any profit.
The goal is to be profitable and we should set some limit with our loses as every investment does not all start well, some starts bad but end up good.
The limit will help us minimize the risk and our loses.