As a per diem social worker, your job is to provide support services as-needed for an individual or a family. This is a daily job where you may be asked to start working on a different case at any time, so the ability to be flexible with your schedule is essential to your success. Per diem social workers occasionally substitute for other social workers who are sick or on vacation, provide extra help when there are more cases than usual, and may work nights, weekends, or holidays as necessary. Companies often have specific shifts for per diem social workers, which could be as little as one or two days each week, so be sure to evaluate the posted hours and determine whether or not they meet your needs.