Advice I got from a professional data recovery expert: Backup your Data... and Backup your Backups... and label your drives! Also, keep a record of what is on your drives.
Like other posters here, I use mechanical drives for backup and mirror them for data security. You can generally get at least two mechanical drives for the price of a single SSD, and if you duplicate your backup then your data is still there if one of the drives fails. If you only have the SSD and it fails, your data is gone for good.
To keep track of what is on all my offline backup drives, I use this indispensable app: https://diskcatalogmaker.com/