Sadly, there is a lot of bad information floating around in this thread. For data to be reasonably safe, it must exist in three separate places. for most people, this would be on the computer, on an onsite backup drive, and on an offsite backup drive. The backup drives must be kept disconnected from the the computer, powered down, and stored away from the computer except while updating the backup. You are already using an external drive so you are off to a good start.
I recommend that you remove your L: drive from your computer and place it into an external drive enclosure. Having a backup drive installed inside your computer, while seemingly convenient, is a bad idea because it is exposed to the same dangers as the other drives in your computer, such as viruses and other malware, PSU failures that fry your computer components, a powerline current surge or voltage spike that plows through any surge arrestors you may have also frying you componets, theft of the computer, accidentally knocking over your computer which damages the drives inside, etc.
Onsite computer backup drives should be stored away from the computer out of sight of the computer, preferably in another room, to reduce the chance of them also being stolen if your computer is stolen. If the computer should catch fire but the damage is limited to just the computer and the immediate area around it, the chances are your data will still be safe.
Since even an onsite backup can be stolen or lost to thest, fire, flood, or other disasters, it is strongly adviseable that you have some kind of offsite backup. This is usually a second backup drive stored as far as physically practical from your home. I used to suggest storing it at a trusted friend's, neighbor's, or relative's home or in a locked drawer or locker at work or school until someone recently pointed out to me that if a home where the backup drive is located gets stolen should that home be robbed, the thief will then have access to your data. Similarly, an employer or school administration could access anything you have in a locked drawer or locker without the need of a search warrant or even a good reason.
The safest place to keep an offsite backup drive is in a safe deposit box in a vault at a bank or credit union. Only you or anyone else you have authorized will be able to access it without a proper search warrant. I pay only $60/year for my safe deposit box where I keep my offsite backup drives. Since I would have the box for important papers that I'm legally required to keep original copies of anyway, the added expense for the additional space for the backup drives was nominal.
Offsite and onsite backups should be swapped out as often as practical to facilitate keeping both as up to date as possible.
I've already recommended using
Macrium Reflect Free to backup your C: drive. Desoite a claim here to the contrary, imaging
is the best way to backup your OS and programs (cloning can also be used but is too time and drive space intensive for backups; it should be used only for vreating a duplicate of the C: drive, such as when replacing it with a new or larger drive). Nigel (Barman58) gave an excellent response for concerns of of backups becoming obsolete. To expand on that, one reason I recommend Macrium Reflect is, even if the company should go out of buiness, you can still use it to make backup images (which must be stored on an external drive, btw) and the images will remain compatible with the OS used to make it, allowing you to still restore them. The media (hard drive, SSD, USB stick, etc.) the image is stored on is highly unlikely to become obsolete during the life of the OS. You still need to be on the watch for when certain media becomes obsolete, as has happened with, for example, floppy disks, but all that is needed to avoid that problem is to make your backups onto current media. Most media today (with the possible exception of optical disks: CDs, DVDs, BDs) aren't going anywhere soon. One precaution you should take is to have multiple copies of your rescue disk or USB drive (I recommend using USB sticks) so you won't be up the creek if one should die on you (or get lost). It wouldn't hurt to store an extra copy or two of your rescue drive with your offsite backups.
While you can just reinstall your OS and programs, you will spend hours to days doing that whereas restoring from an image only takes minutes.
For data only, I recommend a folder/file syncing program used in Mirror mode, such as
FreeFileSync. A folder/file syncing program will compare the data drive (or just a folder, if you choose
With one exception (a paid, cloud backup service; more on that in a moment), you should never use automatic backups since they require that the backup drive be kept connected to the computer, a very bad idea for reasons already discussed. Also, one should always run Antivirus and other antimalware scans immediately prior to backing up anything to reduce the risk of infecting your backups.
If opting for a cloud backup, stay away from cloud storage, especially the freebies, such as Google Drive or MS One Drive. For starters, the free storage options are rarely, if ever, encrypted. Free cloud services of any kind, but especially storage, are subject to disappearing with no to inadequate warning and your data will be lost (Google is especially notorious for discontinuing free services). Most cloud storage options are unencryoted and have more lax security measures, making your data subject to hacking. You are also subject to your data being mined for personal information (in fact, count on it).
A good paid, cloud
backup service, on the other hand, will put software on your computer that will run in the background—you will never see any effects, such as computer slowdowns—and encryt your data before it ever leaves your computer. They usually have far better security against hacking and malware infection. Their servers are in secure, physical locations that are guarded and have backup air conditioning, power generation equipment, etc. to avoid losing data to mechanical and power failures. A good, paid cloud backup service is not nearly as likely to disappear without adequate warning. Paid, cloud backup services are a good option for offsite backups and are the
only kind of automatic backup I recommend. A good, reasonably priced cloud backup service for home systems is Backblaze. There are even better business oriented services but those are expensive. Backblaze was only $50/year the last time I checked (I use a business service).
The major disadvantages of a paid, cloud backup service is cost, the need for a broadband internet connection, and the time required to make the initial upload of data and the time needed to download all of your data if you need a full recovery. The advantages include being able to maintain an onsite backup, including keeping it up to date, with minimal effort.
I use a combination of a cloud backup and offsite backup drives. If I loose the data on my computer and my onsite backups, downloading all of it from the cloud would take months (my ISP's data cap exacerbates the problem). However, I can far more quickly recover most of my data from my offsite backup drives, then recover what little was added or changed on my computer since the last time the offsite backup drives were updated from the cloud backup service. Overall recovery time will go from several months to less than a handful of days
Keep in mind if you use a paid, cloud backup service for offsite backup, you will still need need an onsite backup. Never depend on only one backup.
