It depends on a way how you trade. If you are scalping, then 5% growth is already enough for you, and you sell, to buy some other coin, and then, again, make small, but quick money on it's growth.
But if you are trading long, then it's better to analyse the previous graphic of coin's rise and falls, and sell whenever the coin reaches it's new highest peak (which usually is not too much higher then the previous peak, as every coin has a capitalisation, that influences it's value, which can't increase like immediately.