Investing in Bitcoin requires a level of psychological skill in relation to risk management as the system is volatile it can fluctuate anytime. Everyone has their own choice, their own money, and their own level of risk they can handle so if you can't handle such level of volatility then investing in Bitcoin isn't for you.
Talking about the bold words in your statement, I don't think it's necessary if you are actually doing the right thing, what are you doing with psychological skills in relations to risk management if you are investing with your discretionary income, the money you can afford to lose?
All Investors in Bitcoin are advised to invest with their discretionary income so that you wouldn't be emotional in anyway if your investment in Bitcoin isn't going as planned, so what you are actually saying is not necessary if you are doing the right thing by investing within the confinement of your discretionary income and you are only thinking long term.