IP due diligence often involves requests for confidential information protected by attorney-client privilege and work-product doctrines. Even when shared under non-disclosure agreements, such disclosure to third parties waives those protections unless a "sufficient" legal common interest between the parties can be shown. As a result, attorney-client privileged communications and work-product protections are often waived unknowingly or without consideration. We will explore recent case law and trends in waiver of privilege and work product under the common-interest doctrine and provide practice tips to avoid such waiver during diligence. We will also explore trade secrets, obligations to protect personally identifiable information (PII) and other privacy concerns that can arise during IP due diligence.