It's very dangerous to put all your eggs in one basket. Relying on only one source of income is bad, but we only realize that when something happens to it. As a victim of this, I strongly advocate diversifying your sources of income and starting it early in life.
Someone who only has a few years to retire would not have the opportunity and time to focus on diversification, whereas a young person has all the time, the energy and the money. You can afford to make mistakes and start over.
If you want to choose ways to diversify, it would be good to include both high yield, high returns sources like cryptocurrency, forex trading and real estate. Combining this with low risk and lower returns sources like fixed deposit accounts, mutual funds would help balance your portfolio. The returns from one source can be used to boost the one you prefer later.