At what stage in the development process should error handling be implemented in a large project?

Error handling should be planned and implemented at all stages of development, but key points include:

• Design: define error handling strategies, types of exceptions, logging levels.
• Development: implement error handling directly in the code — try-catch blocks, data validation, proper resource release.
• Testing: verify the correctness of error handling, system resilience to exceptional situations.

In large projects, it is important to have a clear error handling policy from the beginning to ensure stability and ease of code maintenance.