In my opinion, the best time to sell is when the market price of the coin is 20%+ higher than the market price at which you bought the coin. Dont wait till the market price is 95%+ before you sell. That only happens when you got your eyes glues to your machine 24/7. Dont be greedy... Make a little profit and grow it over time. Cryptomarket is growing and full of terror! Be careful
You can always be greedy depending on the market situation, the prices right now is dropping so it was the best time to invest a huge amount.
Which in other words mean to stay greedy when others are afraid. This is a wise statement in terms of availing opportunities. Since this is the initial era of cryptocurrency, it should be kept in mind that the marginal benefits will be very high in long term.
Greed in economic terminology is the name of monotonicity which is the assumption for every individual who is in the market and is taking part in either production or consumption.