In general, it’s appropriate to use explicit type annotations when:
- The assigned value doesn’t provide enough information for TypeScript to infer the type accurately.
- You want to explicitly communicate the intended type to other developers or to make the code more self-documenting.
On the other hand, you can omit explicit type annotations when:
- TypeScript can infer the type correctly based on the context, initializer, or surrounding code.
- The type is obvious and doesn’t add much value in terms of readability or maintainability.