I find that inheritance isn’t that useful when it comes to helping me reason about programs, which is more important to me than avoiding code duplication. The ability to create subclasses can be convenient for adding new code but the same extensibility also means that I have to consider all potential future uses of a class when I’m using one. It’s easy to make assumptions when writing code that uses a class than can then be broken by future subclasses. You can try to mitigate this by writing clear invariants in advance and updating them when you find that you need to make more assumptions, but then this means that you have to give up the flexibility of inheritance.