If you are not able to find discretionary income in a week or month, then the best decision for you is not to invest. Because whenever you are willing to invest outside the discretionary income or invest outside the discretionary income, you will invest the required amount of money and due to this wrong decision, your investment may be at great risk and you may have to sell it at a loss. If discretionary income is not available in a month or week, then definitely stop investing in that week or month and find discretionary income in the next week or month through proper financial management and start investing.
If a person does not find discretionary income in a month. If he has some more funds, such as emergency fund, reserve fund etc., then he can definitely take money from the reserve fund and buy. If someone can be sure that he has enough reserve fund or other funds, then he can do it. But yes, it has to be rebuilt as soon as possible.
I truly understand your main point. but it not necessarily mean investors must figure out discretionary income every single week or month from starting. Fingers are not the same, for some folks, finding discretionary income is a gradual process that comes in better budgeting and learn how to manage their funds properly. So if somebody is unable to invest a single month just because there is not enough funds left after the expenses, that don’t really mean they are failed or they are lazy. That period can be use to plan and improve their finances to invest ahead, what necessary is not to force investment when money is needed elsewhere. I think with period of time when the financial improve, they can lean how to manage their funds more better by gradually creating discretionary income and investing consistently.
Everyone's income, expenses, responsibilities, and financial capacity are not the same. Some people's income may be low, some people's family responsibilities may be high, or their income may be irregular. The first goal should not be to force money out for investment, but to understand your income and expenditure structure. And to develop financial discipline to create investment opportunities in the future. Some people may not have enough money left over to invest after meeting their essential expenses in a given month. It is not reasonable to say that you have not invested, or that you have failed. Analyzing how to increase income, which expenses are essential and which can be adjusted in the future can create some money for investment in the coming months. Discipline in investing and forced investing are not the same thing. Discipline means following your plan. It does not mean that you have to continue investing even if you have a financial crisis. It is not just about buying Bitcoin as soon as possible, but creating a financial system that allows you to invest in the future and does not put pressure on your daily life and important financial responsibilities after investing. If someone cannot invest today, it can be seen as an opportunity to improve their financial situation, learn to budget, and lay the foundation for future investments. As financial capacity increases over time, that person will be able to move towards regular and long-term investments by generating discretionary income more easily.