Best recommended Ext. HD

I'm still very much a novice on these boards and in the PC world.


My biggest fear is 1 day loosing all our family photos and videos.
My main rig has a 4tb HGST int. HDD <--- there are only photos and videos on this. No O.S or software.

I have a 5 year old toshiba ext. HD with 500gb. Works smooth and like new.
I have almost 3 year old toshiba ext HD with 2tb. Runs very very slow. And sometimes not at all.

Can someone recommend me a good quality ext. HD.
I'm paranoid 1 drive will die...

Best recommended Ext. HD