And keeping a second back in an outhouse or detached garage, or with a trusted neighbour is also advisable to cover the awful possibility of losing everything in a fire.
I have a 1TB permanantly backing up my PC drive and an old much smaller capacity device in the garage which I back up from time to time with important stuff, mainly photos jic.
And thanks Gentlemen for starting this post......you have reminded me that I have not backed up to the latter for about 9 months. Off to get it now!!