Now off the top of their head, even if they are not very good at finances, most people have ballpark ideas about whether they can afford $10 per week or not. Now they might not know how to manage their budget, and they might have a lot of debt and they might be having emergencies every month or maybe several times a year because they are not sufficiently spending lower than their income and/or keeping track of their cashflow versus expenses.. .but these are things that people can improve, even while starting to invest into bitcoin.
Now if they are not exactly clear about the level of their disposable income, they may need to get more specific ideas prior to starting to invest more aggressively into bitcoin, such as increasing their investment to $100 per week or performing a lump sum investment of $5k... so the more aggressive that they choose to be, then the more they are going to need to know, and also if they build up their investment amount, then the more that they have invested, the more they could end up getting tempted to cash out at the wrong times or to engage in gambling behaviors rather than investing behaviors.. so most people can learn those kinds of things as they go, even though sometimes they are their worse enemy by doing before knowing.. so if the amounts are small enough, then it might not make a BIG difference, so that would mean that they have their risk management under control by not investing very much, but they may fail to realize their potential because they are not being as aggressive as they could be, including likely needs to pay attention to their whole cashflow situation and to make sure that they are spending reasonably within their discretionary income while maintaining some kind of an emergency fund, float and reserves. which becomes even more important as the investment into bitcoin grows. including accounting for the price changes that bitcoin can go through during the period in which someone is starting to invest into it.
The hardest thing here is to control emotions and psychology. There are many external influences that can make an investor change his plans midstream, including friends or family. Sometimes that is the reason why we don't need to tell our friends and family about investment plans, they can influence us not to take big risks regardless of their support for the final decision. Starting small and going big is much better than the other way around.