Warren Buffett likes to talk about how a key to his success is that he sticks closely to his core competencies so that the business he works on is understandable (see Filter 1 (Understandable First-Class Businesses) in Buffett/Munger’s Four Filters Invention)
As Buffett once explained:
“There are all kinds of businesses that Charlie [Munger] and I don’t understand, but that doesn’t cause us to stay up at night. It just means we go on to the next one…”
I agree and have been keeping a giant post-it note up on my wall with a circle of what I believe my core competencies are (as defined by things I think I do well and also enjoy!). Here’s one version:
