In order to maintain a good Employer Rating, providing feedback within 2 business days is strongly recommended.
As new candidates get submitted, the system will require you to either advance those candidates further into your hiring process, or reject those candidates and provide a disposition reason. You can choose to sort your candidates as they're submitted or simply check in several times a week.
It can be easy to forget that every resume has a real person on the other side, and a real expert recruiter who is working with them. Providing feedback in a timely manner allows agencies to provide the courtesy of timely feedback to their candidates, which will improve your employer brand and ensure the highest quality candidate experience.
Agencies also use this feedback to recalibrate their focus for their next submission, which increases the overall quality of your JobCast. So the more specific your feedback is, the more helpful it is for recruiters to fine-tune their future submissions.