File retention rules allow automated enforcement of how long files must be kept in cloud storage before they can be deleted or archived. They differ from simple deletion policies by ensuring data remains unchangeable and irremovable for a defined minimum period, preventing accidental or intentional deletion. These rules are essential for meeting legal compliance, regulatory mandates (like GDPR or HIPAA), and internal governance policies, automating processes that would be complex and error-prone if managed manually.

Common examples include a healthcare organization configuring rules to keep patient records for seven years to meet HIPAA requirements, automatically preventing deletion until that time elapses. Financial institutions often use these rules in platforms like Amazon S3 Object Lock, Azure Blob Storage immutability policies, or Google Cloud Storage Retention Policies to preserve transaction data for audit purposes. Legal firms might apply different retention periods for various case file types based on case closure dates.

Key advantages are enhanced regulatory compliance and reduced legal risk through enforced data preservation. Limitations include potential increased storage costs for long retention periods and reduced flexibility as administrators typically cannot override the rules during the retention hold. Ethical considerations involve balancing legal obligations with data minimization principles. Future trends see tighter integration with legal hold mechanisms and AI-assisted classification for policy application.