Code Smell 66 - Shotgun Surgery
Say it only once
Bad Responsibilities Assignments
Single Responsibility Violation.
Some modern linters can detect repeated patterns (not just repeated code) and also while performing our code reviews we can easily detect this problem and ask for a refactor.
- Code Duplication
Adding a new feature should be straightforward it our model maps 1:1 to real world and our responsibilities are in the correct places.
We should be alert for small changes spanning in several classes.
Duplication is the primary enemy of a well-designed system.