Performance measurements are only one dimension of code quality. Having a laser focus on it disregards why you would want to sacrifice performance for a differe

Performance measurements are only one dimension of code quality. Having a laser focus on it disregards why you would want to sacrifice performance for a different dimension of code quality, such as extensibility for different requirements. You should check if your code is in the hot path before optimizing, because the more you couple things together the harder it is to change it around. For instance, in Casey's example, if you wanted to add a polygon shape but you've optimized calculating area into multiplying height x width by a coefficient, that requires a significant refactor. If you are sure you don't need polygons, that's a perfectly fine optimization. But if you do, you need to start deoptimizing.