In any case, it is not always necessary to sell coins at low prices. And first of all it depends on the real prospects of the project and how the team works.
Not necessary if you believe that the project is so good. But if it isn't, you should start considering of selling that and move to a better coin as an investment before your money is gone. That's how you take if you value the coin that you have, you need to sell at loss and recover in some other coins or sell if you are contented with it.