It is very important to have a stable income and it is also enough having a stable source of income. This is because a wise person plans his life within the reach of his stable income based on the duration of payments. Basically, any income that can not sustain your basic needs for the duration before your next payment is not also a stable source of income. This implies that for your source to be a stable source, it should be able to take care of your basic responsibilities.
Your comment may appear very discouraging for people who are not working a paid job and those who does not have regular flow of funds and this will make them not to think about investing in bitcoin thinking that they cannot do it. The actually can invest in bitcoin even if they do not have regular cashflow, they simply have to make estimate of their cashflow and work with that to achieve the same result like people who are earning regular income. Someone who do business that is not regular can make a three to six months estimate of his cashflow and from there work out the funds for the basic needs, emergency funds and investment fund and even allocate the investment fund in such a way that he can even use monthly DCA to purchase bitcoin. If you must succeed in any business, you have to plan and what I just explain is part of the planning and execution process.