Having multiple sources of income is good to make available more discretionary income that we can use to invest into Bitcoin. However even the funds from the multiple sources aren't managed properly by being as aggressive as possible without overdoing it and building out our emergency fund and other variances of backup funds in the process of accumulating Bitcoin, our portfolio still has the rights of being tempered regardless of our multiple sources of income.
The purpose of having multiple sources of income is so that you can enough income streams by the end or before the month.
The porpose of having multiple sources of income is not only to have money at the end of the month, but to have a fund that will be able to withstand or handle multiple expenses at once and be capable to solve them without taken loan elsewhere or having to sell your Bitcoin to settle issue. That is the way I can describe my own reasons for having multiple sources of income. And this income has no specific which means it doesn't have time week or month it will come. Some may be an annual generated source of income or could be weekly, but the main priority or goal is to have a well balance financial system to avoid being sloppy in times of Bitcoin investment approach and also avoid unforseen circumstances that may consume us. But with the help of multiple sources of income, it will help to sort this things out without having a second thought of looking for where to source out fund.
For someone not to manage enough income stream, it is possible that no matter the amount he has in life he wont be able to managed them properly. Most investors find themselves in a position where other investors wish to have.
Just like they said, don't dispise the days of your little begining, if little finance can't be managed properly, it is possible that bigger finance can as well not be manage properly too. And that is a financial mistake that every investor must avoid.