I am a big Buffet / Munger follower and use their principles in all my investments. Buffet and Munger suggest sticking to circle of competence. However, I have seen several ETA searchers acquire outside their area of expertise. If we limit search to circle of competence, not only will deal flow go down to a trickle, you will also break the premise of buying niche small businesses - which is where the competitive moats exist. This also brings me to how to define circle of competence. For e.g., I have a PhD in materials science and have done broad enough general mgmt (sales, ops, strategy, P&L, M&A). Should I stick to only materials-adjacent companies (where i doubt there is going to be lot of deal flow)? Or Should I fall back on "I have enough tools/experience to solve any problem" and be open to any sector? And then there is this argument to be made that even if I acquire a company right at the center of my circle of competence, there are going to be unknown problems that will crop up and it is problem solving skills that really matter. How do some of you ETA veterans think about this? How common is it for searchers to step outside their circle of competence?