It is not extremely mandatory to invest a specific percentage of ones income, some persons might be in a situation where they have little or much to spare due to the size of their family and further upkeeps. The actual process is to take out all expenses and funds for reserve then these left overs can be used to invest, going above the spare funds might cause tragic reflexes to one's investment portfolio. I support the fact of investing a fair amount, as long your income is able to cover all expenses and still remain quite a reasonable amount then their should be no hesitate to invest the ideal percentage.
This is part of an effort so that someone can still invest in Bitcoin even though they are spending much more on a daily basis for their own family. Investment is not something that is mandatory for everyone, but everyone who wants to experience profits and financial freedom in their old age. So it's a good idea to think about an investment from now on, such as taking advantage of the potential that exists in Bitcoin by continuing to buy it at a Dip price according to the capabilities that have been previously provided or with an amount that is ideal for everyone who wants to start it for themselves.
It is not mandatory but in a way it is a healthy practice to get involved with, which most people don't find it a possible option. Investing in Bitcoin, does not require whole lot of funds compared to other forms of investment like buying of shares. Bitcoin has made it easy by allowing us invest in divisible units which even an average person would be able to afford from his salary by simply applying the DCA approach which with time (over the years) will give proper return of profits as long the investors holds for the long term and avoid tempering his portfolio.