Before I became a professional photographer I worked in the world of IT and, the time I spent in that field taught me a lot about many things to do with computing but the most important has got to be the proper use and crucial importance of back-ups and backup media.
I could bore you to tears with the ins and outs of complex 20 tape back up rotation or the difference between incremental and differential back up regimes but. . .there is no need!
The long and the short of it is, have more than one copy of anything and everything you may need to keep functioning as normal.
My current working set up is an external "Scratch disk" that I hold all of my working data on, including LR catalog backups, this is more for ease of moving between computers than anything to do with Backups but, With this configuration all I need to work is a copy of Adobe Light Room and my Scratch disk to start working. Currently the disk is a USB 3.0 1TB seagate mechanical HDD which is fine but I would like to swap it out for an external SSD RAID over USB 3.0 which is plenty for Stills, video editing on the other hand you would probably want to go for the thunderbolt option.
In addition to my external Scratch disk I have a another USB 3.0 1TB HDD this time a Western Digital, I could tell you that this is to ensure they are from different production batches reducing the likely hood of two hardware based failures however the truth is I bought them at different times!
Anyway, this disk is for Time Machine, Time machine is a MAC based backup software that runs one big back up when you set it up and then after that it keeps realtime changes and as you work as well as daily, weekly and monthly backup and as you fill up space on the HDD it deletes the oldest backup to make room. This backup includes my scratch disk which is always handy! If the scratch disk failed I could use the Time Machine to restore onto a new disk or even re-image the current HDD after a file corruption for example.
I guess the best backup system is the one you have but I would always recommend that you don't rely on one method. It is true that one method is better than none but, two is always safer than that. My set up is very simply implemented. It requires basically one or two external HDDs and in my case Time Machine but the same setup can be achieved with Windows Backup software in built with all Microsoft operating systems.
The reason I posted this was because I recently had a HDD start to get flakey and it made me reevaluate my backups and how I would have kept working if the disk had failed, turns out I wouldn't have, some stuff from that disk, mostly archived images from old jobs thankfully, would have been lost completely, I now have 2 copies of my working data on separate external media. So my advise at the very least.....(Select all > Copy > Paste to 2nd HDD) but for the ease of setup and time it takes and the £40 price of a HDD do it properly!
I hope this helps, but please feel free to get in touch if you want any more info or help with this setting up your own backups.