Prefer Result for Recoverable Errors: Avoid panic! for expected failures. Use Result to give callers control over error handling.
Propagate Errors Upwards: Use ? to propagate errors cleanly. Let the function ultimately responsible for handling the user interaction or application state decide how to manage the error (log, retry, default, report). Avoid handling errors too early if the caller needs more context.
Provide Contextual Error Information: When creating or mapping errors, add context about what failed and why. Custom error types (using thiserror or manual impls) or anyhow::Context are excellent for this. Good error messages drastically improve debuggability.
Use unwrap and expect Sparingly: Only use them when a panic is acceptable or when program logic guarantees the operation cannot fail. In most production code, prefer explicit handling via match, if let, combinators, or ?.
Choose the Right Error Strategy:
For libraries: Use custom error enums (often with thiserror) to provide stable, specific error types for callers.
For applications: anyhow or Box<dyn Error> can simplify error handling when granular matching isn’t the primary concern.