The most important restraint is the ability to have other sources of income so that you can keep your crypto currency fo as long as possible to a time that will favour you in the market. That is, off you are not in a hurry and if you do not lack money, then there's no need to sell hurriedly. Take your time to analyse the market and see where it takes you to positively.The main reason that anyone buys crypto, invests in it, or even earns it, is so that they are hoping that the coin will increase in its value in the future and there will be able to profit greatly from the time and money that they invested into it. Since bitcoin has been rising, there have been some people such as myself that sold it at a value that was around 15k USD, for fear that it will not rise past that point. Some however were able to hold their bitcoin for these high prices we are seeing now, profiting much more from it.
What was your self-restraint on your bitcoin holdings? What was the price at which you sold your bitcoin or are you still holding it?