A word to the wise . . .

Take a look at these articles:

Resolve iOS update and restore errors in iTunes - Apple Support

Get help with iOS update and restore errors - Apple Support

Never wise to rely on a single source backup strategy for any data, IMO. So I fully agree with you - use both iCloud and iTunes. I also backup my iTunes backups in Time Machine, and I keep an additional two complete system clones of my Mac as well (one updated nightly, and one updated weekly and kept in a fire proof safe).

Also make sure to check you iCloud backup periodically - check that your device has in fact completed a backup recently and is not reporting errors. If you suspect a corrupted iCloud backup, delete it, plug in the device and manually execute a backup and make sure it completes.

Michael Black wrote:

Also make sure to check you iCloud backup periodically - check that your device has in fact completed a backup recently and is not reporting errors.

The question is how would you know iCloud data is not corrupted without restoring it for real? A backup is a good backup only if it's proven to restore successfully. Unfortunately the only time we need our iCloud data is when there's a problem with our device.

ShagCA wrote:

Michael Black wrote:

Also make sure to check you iCloud backup periodically - check that your device has in fact completed a backup recently and is not reporting errors.

The question is how would you know iCloud data is not corrupted without restoring it for real? A backup is a good backup only if it's proven to restore successfully. Unfortunately the only time we need our iCloud data is when there's a problem with our device.

I agree. You don't know if the backup is corrupt, unless you restore it, but you can check to make sure that the backup has completed. If the backup doesn't complete, that could be a sign that there is something wrong. I emphasize the word could because there may be other reasons why the backup didn't complete, but checking to make sure the backups are taking place is a good starting point.

Just like an iCloud backup, an iTunes backup could get corrupted as well. Sometimes you don't realize that until you try to restore the backup. There is no perfect solution and that's why backing up with frequency is a good idea. When I create backups in iTunes, I will archive one every so many times that I backup, so that I have what I hope will be a few recent backups from which to choose, just in case.

Actually, one way you DO know if your iCloud backup is corrupt, or likely so, is if you check and find that it has not been updated in several or more days. When automatic incremental iCloud backups fail repeatedly, that's usually a pretty good indication you have a bad backup file in place in your iCloud storage. That's why I said to check periodically that your device is at least reporting successfully having completed recent backups. We've had posters who were blithely unaware that their iCloud backups had in fact not been completing for weeks or months.

Of course the only way to be sure a backup is not corrupted is to restore from it, but there often are some pretty clear signs that something is amiss, if your checking and paying attention to them. The problem with automated backups is people set them up and then forget or ignore them. You need to keep a periodic eye on the whole process - that's my only point. And of course as your first post proved, redundancy gives you some assurance of surviving a single point failure.