What is a lifecycle policy in S3, and how can it be used?

Cost Optimization: Automatically move infrequently accessed data, such as logs or backups, from expensive S3 Standard storage to lower-cost tiers like S3 Standard-IA or S3 Glacier Deep Archive . A policy might, for example, move logs to Standard-IA after 30 days and to Glacier after 90 days, then delete them after 365 days .

Automated Data Retention and Compliance: Enforce data retention policies by automatically deleting old data after a specified period. For instance, a financial services company can use a lifecycle policy to retain transaction logs in S3 Standard for 30 days, then transition them to S3 Glacier for long-term archival, and finally delete them after several years to comply with regulations .

Managing Old File Versions: In buckets with versioning enabled, you can use lifecycle policies to manage previous (noncurrent) versions of objects. For example, you can create a rule to automatically delete noncurrent versions after 30 days to prevent storage costs from accumulating .

Cleanup: Automatically delete incomplete multipart uploads or temporary files, preventing them from consuming storage indefinitely .