Methods for automatically identifying and instrumenting application classes and methods for a particular application are described. In some embodiments, application code (e.g., bytecode or source code) associated with the particular application may be parsed to identify classes and methods within the application code and to identify terminal components (e.g., methods or function calls) and non-terminal components (e.g., control flow statements). Once the terminal components and non-terminal components have been identified, a complexity model and a corresponding score for each of the classes and methods within the application code may be determined. The complexity model may be used to estimate the number of computations that may be required if a particular class or method is used by the particular application. Application classes and methods corresponding with a score that is greater than a threshold may be instrumented by inserting probes into the identified classes and methods.