As humans, we all make mistakes, and sometimes, users provide incorrect data that doesn't meet input criteria, preventing the system from submitting the form. To value users' time, it is important to inform them about these errors promptly, instead of waiting until they hit the Submit button. Therefore, it is recommended to validate each input after users fill in the information and move the focus away from the input.

To provide effective feedback, the error message should be concise yet precise, clearly indicating what went wrong and how users can fix the problem to continue with their task.