6) Always Remember That Everything Is Relative. The best way to determine worthwhile passive income streams is by comparing the likely return (IRR) with the current risk-free rate of return. If I round up, the 10 year bond yield is at 3%. Any new venture should thoroughly beat 3% otherwise you are wasting your efforts since you can earn 3% doing nothing.
For a person working for a wage, their source of income is their job, or their labor (aka their time that they sell to someone). But you can own a house, and rent it out, and when your renters pay you renter every month, the source of that income check is your rental property, or your house. It would just be called rental income. If you have money in the bank in an account that pays interest, those interest payments are another source of income. We can say the source is interest payments, or we can identify the asset that is generating rent, and say your money in the bank that is generating “rent” (aka interest) is your source of income.