it all depends on your seriousness of what you want to learn for example, want to be a professional in the cryptocurrency field you have to learn more and more about it, so if you don't do anything for 1 or 2 years you'll never become a pro. for three or four years i think it would be enough if you study it more.
we don't make measurements for this problem. where to be very good at cryptocurrency or otherwise, all depends on the willingness and level of understanding of yourself. sometimes we are just enthusiastic about learning at the beginning, and feel bored after a few months.