I keep all my photos in the C:\users\myname\my documents\ folder. LR works from there, too.
I have a backup hard disk installed in my computer. I use batch files to manage backups but it is easy from the command line. Enter the following on a command line:
cd \users\myname
xcopy /d /s /y *.* e:\users\myname
This will copy all user files (photos, LR settings) to drive E:\.
If you want to be more specific (photos only?), add \directoryname\ to the xcopy command.
The first time you run this it will copy everything. Next time it will only copy new/modified files.
To run it to an external drive, just change E:\ to the proper drive letter.
It doesn't get any easier. I run this on my internal backup drive a few times a day, and on my external drive at least once a week. My HDD died in May. I lost nothing. I was back up and running in less than an hour. OK, I do keep a spare, blank HDD on hand for just such occasions. Learned that from experience. A new, blank $59 hard disk, safely stored away, has saved my bacon more than once.
Retail backup software is several things: expensive, confusing, sometimes proprietary, not supported by the time you need it, inefficient, slow.... the list goes on. Running this kind of stuff is completely free, updates everything in a format you already know, and is completely free. On top of that, you can update and modify it yourself if it doesn't suit your current needs.