The 8-Minute Rule in therapy is a Medicare guideline used to determine billing units for time-based therapeutic services such as physical, occupational, and speech therapy. Under this rule, therapists can bill one unit if at least 8 minutes of a single, direct one-on-one service is provided. Each additional unit requires approximately 15 minutes, but the rule allows flexibility in total time, so multiple services can be combined if their total time meets the threshold for additional units. This rule helps ensure accurate reimbursement for the time therapists spend actively treating patients during a session.