I remember the time where BTC reached this price peak and I refused to convert it to cash thinking that the trend would to increase. A few months after such peak, its price dropped and slowly it failed to recover from this price point.

I definitely agree with your statement- if the price increases tenfold or at least the initial price, then it is a good time to sell at least 50% of your total coins. You will definitely never know when its price would increase/decrease as it is also dependent on current events.