Migrating from an old warehouse or lake to a new one requires careful planning and execution. Key considerations include identifying the necessary data, setting up replication processes without disrupting ongoing updates, and ensuring data integrity during migration. A typical warehouse migration process can take anywhere from a few months to two years. Tools like Fivetran can support this process by simplifying object selection, setup, and automated replication. Database replication pointers include using log-based replication when possible and implementing change management strategies. Data quality safeguards involve monitoring for freshness, volume changes, and numeric distributions to ensure data integrity during migration.