Best practice: Local + Offsite (to cloud) backups are essential. Why not use a backup software with local and cloud backups capabilities to automate everything for you? Products like CloudBerry Lab (www.cloudberrylab.com) and CloudBacko (www.cloudbacko.com) are specifically designed for such purpose. Not expensive at all. For backup locally, just buy a 4 – 5 bays NAS that would be enough to store all your raw unedited videos for several years. For backing up to cloud, Amazon S3 and Google Cloud Storage are both good and supported by the two software. It's only around $0.03 per GB per month. Not too expensive. If you like to save some spending, maybe just backup those edited ones. Just my two cents.