I sincerely apologize for not responding sooner--work has been crazy as we finished up stuff before the holidays.
So, I followed your advice and erased the external drive and started over. It worked really well. After I did my first backup, only 7% of the drive was being used. But here's the thing: it seems to be filling up relatively quickly--roughly 0.5% a day. I'm just working from home, and I don't save huge files. In fact, I'm constantly emptying my download folder, emptying the Recycle Bin, and moving important files to my job's One Drive cloud storage.
I bought this computer and the external drive in fall 2016. I use my computer constantly and it has been working beautifully since I got it. The external drive only became "full" recently. There was one incident, however, that may have had something to do with it. I hadn't looked at my external drive in ages to check on it, and when I did (this was last month or late October), I noticed that it hadn't done a backup since June 2021! I immediately researched the issue and updated all the Western Digital tools. I discovered that support for WD Backup had ended and that I now needed to download Acronis True Image for Western Digital, which I did. After doing all these updates, my external started backing up every hour as it had done in the past. With one difference, though: my external hard drive started to fill up quickly.
Apologies if this is a stupid question/conjecture, but I thought that the external drive backed up one's computer at a given moment. Let's say I had 30 files. Then I wrote some letters, downloaded some stuff, and took some pictures of my cats. The external would back up everything that was present at the time of the next back up. Then, let's say I deleted all the my downloads, emptied the garbage, and was left with only 40 files. I'm assuming that the external does not save all the stuff I deleted, correct? Or does it save a 'version' of the computer at every juncture? I just want it to back-up the most current version when it does its back-up. Does that make sense? I'm not sure whether I'm explaining this clearly. (And I obviously may not understand how external drives operate!)
My computer says that all my drives are healthy and that everything is functioning as it should be. When I have time, I will investigate cloud storage since I will probably be moving to another country soon, and don't want to risk losing everything in the move.
I would love to hear your thoughts and any additional guidance you might have re the external hard drive and cloud storage when you have time. Many thanks again for all your help, and once again, please forgive me for not responding sooner.
I hope you have happy holidays!