Asides the DCA, Bitcoin investment is for those with a steady paying job, not for people that wants to risk their cash to make quick money, someone without a job can't even hold for long cause they'll be forced to sell during time of emergencies, their only hope would be one their investment since they don't got other money therefore it's not advised and whether DCA or not an investor should have a job already.
There are many people who do not have a monthly salary. But they have a stable source of income, they can invest using the DCA method.
Many have a daily source of income, they can buy Bitcoin using the DCA method. Whether you have a monthly salary or a weekly salary, you can buy Bitcoin using the DCA method if you have a stable source of income. Because if you do not have a stable source of income. Then you may not be able to continue investing in Bitcoin consistently.
As soon as you invest, you need to create a reserve fund and an emergency fund. So that when an unexpected disaster happens to you, you do not have to sell your saved Bitcoin. Always try to keep 3 times your stable income in the emergency fund and reserve fund.
DCA strategy is not only for people that are working and receiving salary monthly or weekly it is also for business people and if you are a business person and you are always making profit daily you can decide to Accumulate daily.
Yeah you are right without a stable source of income is not possible to invest in Bitcoin the reason is that if you don't have a stable source income and you are investing in Bitcoin you will always be tempted to dip hands into your Bitcoin to still home bills like shelter, food, clothes, electric bills etc. Even if you have a very strong emergency, reserves and float funds you can't still succeed in Bitcoin investment without having a stable source of income the reason is that Let's take for example maybe when you has a very good stable source of income you built a very strong emergency, reserve and float funds if you start using all this funds without adding to it again it will finish and when it finishes you have no where to run to anymore apart from your Bitcoin investment so if you want to succeed in your Bitcoin investment you need a stable source of income no matter how little it is.