Yoyo's blog

Sleep before learning, so that you can absorb new knowledge like a dry sponge, if there is no sleep before learning, it will be like a wet sponge, there is no way to absorb more knowledge. Sleep will not only affect the memory, even the ability to reproduce will also have an impact, so we should have a normal work and rest, so that their health is better

It can take up to 10,000 hours to learn something to the level of proficiency or even expertise, but we don't usually have that much time to divide between different things to learn.  So from not knowing to knowing, the author points out that it only takes 20 hours, which is a great thing, but it still needs to be practiced over and over again in order to become proficient.