I haven’t studied the dt file system; I do back up the AppData files (Windows) daily, but I don’t rely upon them. When I download images from my camera, I copy the folders from my camera to my H drive and rename the camera’s folder name using the format YYYYMMDD. That format lists the folders in my file manager in correct chronological order. All those files are backed up daily.
When I want to develop a photo, I create a folder just for it. When I open the folder in dt, it puts the xmp in that photo’s folder on the H drive. xmps for all my duplicates are also put in that folder by dt.
In addition, I look at Play Raw posts all the time, and when I want to try my hand at developing an image, I create a folder for it on my H drive and put the image file in it. I also download the xmps that are posted by others. I copy the username of the person who made the xmp, and then I punch a key on my auxiliary programmable keyboard, and that changes the xmp file name in the Save dialog by putting the username in the file name. When I want to study someone’s development, I create a duplicate in dt and load that person’s xmp using load sidecar file. I keep a text file in the folder in which I record which duplicate goes with which xmp.
Each image’s folder gives me something I can look at to see where things stand. If I had to restore my files, I would know exactly how to do it.
It is true that in darkroom you can name the duplicates using duplicate manager, and I sometimes do that. A particular downside of relying on dt, however, is that I have opened a folder, done development on an image, and then dt crashed. When I opened dt up again, it did not know that I had opened the folder in the first place. Since I use the compact history function frequently, I know that I can go to my image folder on my H drive and load the xmp and be back or almost back to where I was before the crash.
Maybe there is a better way to do it, but I like the system I have worked out, and I have peace of mind.