There's no general answer to how often. It depends on how you use your computer. I do a full backup once a month, with incrementals intervening.

Thank you. @@askleonotenboom

@@Merichguy2 By doing incremental backups, you should (depending on the software) be able to restore files from each backup session. In other words, if you do a weekly incremental backup, then you can restore files from week#1, or week#2, etc. That is helpful if you screw up a file without realizing it. You might have to go back a few images (a few iterations of your incremental backups) to find that file from a time before you screwed it up. Even if you do a monthly full backup (as our host does), you do not need to delete the previous month's full backup (if you still have enough free space on the drive holding your backups). If you delete your full backup, followed by starting a new full backup, you run a risk of data loss. It is a very slim risk -- but still a risk. At the moment you delete your full backup, then until you compete another full backup, you have no backup. So while performing your full backup, if your source disk dies, you will not be able to complete your full backup. Now you have a real problem, because you do not have any backup. I suggest that when you start a full backup, you always keep your previous full backup. Never leave a moment where you have no full backup. But those incremental backups are handy for grabbing files in the state that they were in on each date you did the incremental backup. One other precautionary point: It is convenient to leave your target drive connected all of the time. When your backups run, you do not need to plug your target drive in to a USB port. However, that convenience is risky. If a bad actor gets control of your computer (like a ransomware attack), you do not want your drive that contains your backups to be connected to your computer. Also, keep a copy of your backup installation file on your target drive. If your C: drive dies, you will want to have your backup software on your target drive. And keep a copy any registration code, etc, that you will need for you to be able to use your backup software. In other words, if your C: drive dies, then have everything that you need on your target drive to get you up and running when you replace your C: drive. If your backup software includes creating emergency boot media, then get a flash drive and have it be your emergency boot media.

Restoring to a VM is equivalent to restoring to a completely different machine. It might or might not work. More here: askleo.com/move-my-hard-drive/

I had a similar question, that I asked on the channel "ExplainingComputers". I wanted to make an ISO of my old, daily driver computer. Then I wanted to purchase a new computer, and be able to run my old computer's ISO as a virtual machine. Once that was working, I could toss my old computer, and reclaim some desk real-estate. My question was from 2 or 3 years ago. His answer was "No." I do not recall why he wrote no. I do not believe that youtube has a search feature to find such a comment.

@@NoEgg4u Many thanks for that. I ran Macrium last night just for the hell of it. This morning when I looked at the file, I note that the file extension is MRIMG which makes me wonder if it is proprietary. I'm going to change the extension to IMG and give it a try. Nothing to lose.

@@DavidM2002 I had installed Macrium Reflect when they offered the free version. I wanted to try it out. It kept nagging me to upgrade. There was no way to disable the nagging. I got fed up with it, and uninstalled it. I now use EaseUS ToDo. It had a couple of issues. But their customer service was responsive and got me a fix. But as to the possibility of creating an ISO, and using it for a virtual machine, I hit a dead end.

@@DavidM2002 MRIMG likely refers to Macrium Reflect IMaGe.

Most backup programs do compress. Both Macrum and EaseUS do.

@@askleonotenboom I'll have to look as those. The backup software I'm familiar with will compress files and folders, but not disk images. You may have helped me find a better safety net for my computer.

I use Seagate's free disk cloning SW. It takes about three hours for my 1 TB drive. I run it before I go to bed.

@@stevencooper2464 A 1TB source drive does not require a 1TB target drive, unless both of the following two conditions are true: 1) You do not use compression. But as our host wrote, most backup software does. It is an option, usually defaulting to "medium". But you can choose none of maximum. 2) Your source drive is full. If your source drive has 300GB of data (700GB of free space), then your backup (even with no compression) will consume 300GB of space. Some backup software offers a sector by sector option. I believe that option will copy empty space? I have never heard of anyone using the sector by sector backup option. I never read about a situation where using that option would apply. For a standard full backup (not sector by sector), the image file that will be created on your target disk will be roughly the same size as all of your files, combined (if you use no compression), and much smaller if you do use compression.

All we can say is maybe. It depends on the specific drivers, the specific changes, and more. Windows will TRY hard to run, and might, but there's no guarantee.