I'm a heavy user of type hints and enable pyright and mypy's strict modes whenever possible. However, you can't always be strict: if you use almost any package

I'm a heavy user of type hints and enable pyright and mypy's strict modes whenever possible. However, you can't always be strict: if you use almost any package in the data science/ML ecosystem, you're unlikely to get good type inference and checking[1]. In those cases, it can still be useful to type some parameters and return values to benefit from _some_ checking, even if you don't have 100% coverage. Type hints also bring improved completion, which is nice too. [1] For example, huggingface's transformers library decided to drop support for full type checking because it was unsustainable but decided to keep the types for documentation[2]. There are stubs for pandas, but they're not enough because pandas has a tendency to change return types based on the input, and that breaks quickly. [2] https://github.com/huggingface/transformers/pull/18485 https://github.com/huggingface/transformers/pull/18485