Generally, our investment should be done based on our income flow/ the level of our discretionary income and our personal designation to carry out this operation based on this in such a way that it suits us by not negatively affecting our other life, it doesn't necessary matter how and when, what is most prioritize is your level of consistency which is very paramount as way of increasing the size of our holding and the chances of having an overall reasonable size of Bitcoin over the long period of time.
Referring to our own income level is the same as referring to our own ability in everything including making long-term investments in Bitcoin. I also think that this is good because there is no element of coercion in doing it, moreover it can also make ourselves a little comfortable in doing it more routinely and also more consistently in the long term. So I also agree with the idea you expressed because if we compare it with the level of coercion in doing something like in this investment example, of course the level of consistency will not be too visible in our own efforts. So this does need to be measured from the level of our own ability through the income we get every month so that the investment work we want to do can continue to run smoothly for a long time.