Backing up your photos and videos is critical! I dislike being so doomsday but it is just a matter of time before you suffer a hardware failure or make a mistake and delete files. I get these emails from my viewers - "help! My photos are gone" and it breaks my heart!!
My Backup System
I have a large and fast working drive - The LaCie 6Big with 36TB of fast storage
ALL photos on that drive are backed up to a slow but reliable 10TB drive. The easiest and cheapest option I can currently recommend - The WD 10TB USB 3.0 Drive. It's slow but that doesn't matter for backup.
And my big working drive is backed up ONLINE to Backblaze - the best online backup system - currently just $5/mo for unlimited storage of ALL files and ALL external drives plugged into your computer. Signup here for a FREE month.
If you don't need that much space (and most of my space is video files, not photos) I can recommend the following system
This SanDisk 2TB USB 3.1 SSD is incredibly fast, rugged and super portable. With SSD drives you don't need to worry about babying the drive - just toss it in your bag and go.