Understanding your circle of competence helps you avoid problems, identify opportunities for improvement, and learn from others.
The size of that circle is not very important; knowing its boundaries, however, is vital.
You have to figure out what your own aptitudes are. If you play games where other people have the aptitudes and you don’t, you’re going to lose. And that’s as close to certain as any prediction that you can make. You have to figure out where you’ve got an edge. And you’ve got to play within your own circle of competence.
If you want to improve your odds of success in life and business then define the perimeter of your circle of competence, and operate inside. Over time, work to expand that circle but never fool yourself about where it stands today, and never be afraid to say “I don’t know.”