Have you ever thought (as I did today) that you would burst into tears or have to break open a bottle (before noon!) if you lost Lightroom work you did or images you captured? If so, you are going too long between backups.
Let’s first go back to a public library analogy for Lightroom: if the stacks of books burned down but the card or web catalog was saved, could the library function? Could it function if the stacks were saved but the catalog was destroyed? Of course the answer in both cases is no. It is true that it would take less time, expense and effort to recover from the catalog destruction, but both are critical pieces to the functioning of the public library. With Lightroom, your images are like the stacks of books and the Lightroom catalog is like the card catalog in the library. When you think of backing up your photo library, you need to plan to back up both the images and the Lightroom catalog.
It is obvious what you lose if your hard drive crashes and you lose all your images, but what do you lose if you lose your catalog? YOU LOSE ALL OF THE WORK YOU HAVE EVER DONE IN LIGHTROOM — your keywords, ratings, flags, entered metadata, develop fixes and enhancements, collections and more. (Yes, if you are saving to XMP you might still have much of your work, but that is a topic for another day.) Could you recreate what you would lose? Perhaps — but do you have enough free time and patience to do so?
My first recommendation is that you store your images and your catalog in one folder (which I’ll refer to as your photo library folder), so that you know that all you have to do is back up this one folder. This folder can reside either on your internal hard drive or an external drive. By default your catalog is in a folder called Lightroom in your My Pictures or Pictures folder on your internal hard drive. If your images are also there and you are happy with that, you are set. (If you regularly work on two computers, having your catalog and images on an external hard drive has the advantage of allowing you to easily move from one computer to another — see my post on this topic.)
If you are not sure where your catalog is, or you know where it is and you want to move it, see this post on how to do so.
If you don’t want to move things around, that is fine — just make sure that you understand that you need to back up both your catalog and your images.
Once you know where things are, backing up is pretty straightforward. While you could do a straight copy to a backup external hard drive, this manual approach becomes tedious over time. It’s better to use a backup program like Time Machine on the Mac, Windows Backup on the PC, or one of many third party programs — a colleague of mine recommends Acronis True Image for the PC, and Carbon Copy Cloner for the Mac. Advantages to using a backup program include (1) that the backup is verified, so you can be sure it was 100.000% successful, (2) it can be scheduled, so it does not rely on you to remember to do the backup, and (3) after the first backup is done, future ones only copy things that have changed, so it is quicker.
How often should you do a backup? Frankly, it depends on how risk averse you are and the stakes involved. If you photograph or work your images every day, and it would be emotionally or financially distressing to you to lose any of this work, then back up every day. If it would be upsetting to lose even one day’s work, back up after 4 hours.
How many backups should you have? Again, it depends on how risk averse you are and the stakes involved for you. At a minimum have a backup on site for convenience, and one offsite or online, in case a burglar breaks in and steals all your hard drives. For an online backup, I use Backblaze because it’s inexpensive and automatic – the first backup of my 3 TB or data took several weeks, but now it just automatically backs up everything new that I do.
So what about the Lightroom-guided backups that you are prompted to do when Lightroom closes? Contrary to popular belief, these are just backups of your catalog, and not your image files. This backup is critical as well. Lightroom catalogs can become corrupted and unusable. It doesn’t happen often, but it does happen. If corruption occurs right before you do the hard drive backup discussed above, all you have on your backup drive is a corrupted catalog. You also need more backups of the catalog spread out over time, so you can get back to one before the corruption occured. This is what the catalog backup prompt is for. I put these backups on the same drive as my main catalog, in a Backups folder in my catalog folder (By default, PicturesLightroomBackups). As a result, I have backups on my main drive, and backups of the backups on my backup drive. I like the redundancy that this creates.
I have Lightroom prompt me to do this backup once a day. If I haven’t done any significant work, I just hit the Skip button. To change the frequency of this prompt to whatever works for you, up in the menu bar in Lightroom go to Lightroom (Edit on a PC) > Catalog Settings.
I recommend occasionally going in and deleting many of these backups, because they accumulate and over time consume a tremendous amount of hard drive space). (See my post on deleting backups.)
In summary, I do a hard drive backup (of my photo library folder as well as of all my other documents) every day or two to a backup external drive, I have a cloud backup program running all the time (BackBlaze), and I back up my catalog every time I have done any significant work (otherwise I hit the Skip Now button). Figure out a plan that works for you, and stick to it!