No matter how good the fundamentals of the coin are, if a coin goes more than 100% within 24 hours I absolutely sell them. A classic case of this has been Storm coin, it has already dipped about 50% from its ath after it went crazy just a couple of days ago.
Exactly, I think you should first check why the value is soaring, Usually after such pumps, there is always a correction in the coin. So it's better to sell when the others are buying and then later buy again when others are selling and the market is crashing