Actually Before I comment on HODL or no HODL, I need to say it depends how you purchased the coin and at what price.
Suppose I purchase something at $100, it means I am confident on my research that its price is $100, if now market start trading at 90$ and my research still says it is good at $100, then I will HOLD. If I now come to some new facts that make me believe that it actual price $80. then I will sell at $90 at once.