Mental models are simple expressions of complex processes or relationships. These models are accumulated over time by an individual and used to make faster and better decisions. Here’s an example: the Pareto Principle states that roughly 80% of all outputs comes from 20% of the effort. In the context of product management, the model suggests that instead of trying to create 100% of the customer opportunity, you may want to look for how to do 20% of the effort and solve 80% of the opportunity. Product teams make this trade off all the time, and the results often looks like feature launches where 20% of customers with more complicated use cases aren’t supported. Mental models are powerful, but their utility is limited to the contexts they were extrapolated from. To combat this, you shouldn’t