Not just an actual 10% of what we earn, it could be more or just less depending on our level of accounting for paid expenses and bills, savings and reserved funds including every other minor fees. The whole concept should be investing at ease, and not above budget putting the investor at risk of going shot from what he has left. All strategies are unique, either using any we still get profits from using them, the only avoidance is not spending much or aggressively entering the market which will definitely have a regretful impact in our proceedings.
10% is from the income we get every month. This means that it is smaller compared to those who are able to budget 20% to be invested. So that everything can run smoothly, you can use the other 90% by managing it as well as possible in the coming month, so that the Bitcoin accumulation process will not be disturbed.
I think it has been emphasized by many contributors here that there can never been an ideal percentage of funds that should be allocated to Bitcoin investment because it is something the individual should work out based on several factors. The percentage two individuals receiving the same salary will invest in Bitcoin differs because both might have different responsibilities. It is therefore not proper to allocate a percentage of personal income an investor will invest in Bitcoin. Another thing to also put in mind is that people have different priorities even as they plan to invest in Bitcoin. Someone might prioritize investing in Bitcoin and will allocate higher percentage than another one that might also have other priorities and can therefore go for lower percentage to be invested in Bitcoin.
What is most important is to invest an amount that will not represent so much financial burden on the investor so that the investment can be held for a long period of time because it is in long term investment that Bitcoin is best. This bring to mind the concept of DCA that allow the investor invest in a manner that will not be so much stress financially.