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
Is not necessary that one should even wait until the price grow to the level of 20 percent and above before one should sell, but advising people to sell when they hit their target point which some times could even be less than that of the 20 percent profit as you rightly mentioned above. And I want advise people not to set high target except you want to hold a long time period.