Glad to help and good, continued clarifying questions. But, I am unclear if you're making a statement or asking a question on the part = "So when LR imports it also exports the file CR2 plus the edits .xmp to my chosen folder as above."

You can do an export of file format = Original. This sends a copy of the CR2 and the XMP sidecard to the target folder. You should confirm you're automatically creating XMP files by checking: Edit / Catalog Setting / Metadata and you've checked - Automatically Write Changes Into XMP. Assuming you checked this box, the export-Original is now a duplicate of both the CR2 file and the XMP file into the target folder. This would be redundant and space intensive if done for all RAW images on a regular basis, particularly given your description of backing up your primary storage, including the source files of the images.

Maybe an example will help. Take RAW image IMG_1234.CR2. This file is created by an EOS camera. When copied onto your computer, nothing changes about IMG_1234.CR2 except a copy of the file now exists at some location on your computer (or an attached external drive, if applicable). As mentioned by other comments, a RAW image cannot be updated, except maybe by the manufacturer's software. In the case of Canon CR2 files, the DPP software can "extend" the file with additional data known only to DPP. However, the original image is not updated, only data is added to the file.

Now for 3rd party software such as Lightroom, ON1, Photoshop and so forth, how those softwares store edit information is somewhat software specific. Lightroom retains all the data inside a database specific to LR, aka the catalog. Other software might create a "wrapper" like a DNG or PSD. Another common option is something called an XMP. For LR, an XMP file is in addition to the data stored internally to LR. If you were to lose your LR catalog (the database of the edit and location data), you could partially recover be first restoring the LR software and then re-importing the images and their XMP files. There are some aspects of the image catalog, collections for example, that are not stored in the XMP files.

So to your question / assumption above, you'd have to explain a bit more about your word choice of "sends". When you view your edits within LR, you see a rendered version of your edits. These edits exist only inside LR, and if you've configured your LR software to create XMP "sidecards", your edits are also in the XMPs. As said before, the edits have not been made directly to the CR2 files. Rather, the CR2 file and the XMP sidecar are needed to merge the edits against the image to render a view of the edited file. The CR2 alone or the XMP alone cannot be used to render the edits. They both are needed by LR.

To see and / or share those edits in a finished file, you need to Export those edits to a viewable file type, typically a JPEG or TIFF, where other options also exist. I share images to several social media sites where I've developed Export presets to render images with the resolution and JPEG quality characteristics appropriate to those sites, including a watermark, etc. As mentioned in an earlier comment, at an earlier point in time I was exporting my edits and discarding the original files. Only later did I understand the amount of data that was lost by discarded the CR2 and keeping only the processed JPEG.

Reading your now several comments, I'm a bit unsure of your exact process. If you haven't discarded your CR2 files, you're still in a good position. If you're keeping both the CR2 file and the XMP side card but removing the image from the LR catalog, you haven't lost everything, but this not a best practice where LR is intended to be a long-term look-up database of all your images rather than a short-term work-in-progress tool. But, if you're deleting the CR2 files, you've lost (or at least severely limited) your ability to revisit the RAW images.

First of all, you do not have to use a 2-step process for importing images. When you import into LR, you can set it up so they go into a specific folder, or you can simply import without specifying and they will appear under "previous import". From there you can distribute them to existing folders/dates, or create new ones as needed. As long as you have the same folders set up on your hard drive and in the LR Catalog, it will go smoothly. [If you create the folder inside LR, it automatically is set up in the same folder on your hard drive.] Remember that photos seen in LR are not IN LR - LR "reads" those images and displays them. [This is why all changes must be done from within LR, otherwise the connection is lost and LR will not be able to "find" the image.]

As long as you continue to use LR, you will be able to see your images. But if you want to look at them without LR, you will not be able to see those edits [.xmp sidecars]. Also, if you are doing PP directly on the original, it will no longer be available for you to use for further edits or for comparison to the changes you have made. If you are working on a proof [or virtual] copy, then you will be able to see the original, but not the edit, outside of LR, unless you export it with a format such as .jpg, .tiff, etc.

It seems to me that the backup system you have is good. But it should also include those originals you are deleting. No matter what system you have chosen to organize your images, whether by folders, date, location, etc. there should be a special place to store unedited originals. I keep my originals in a folder marked "support photos", along with some images that I made as I was doing my edits [different stages, or different variations]. This folder is always in the same general folder that includes separate sub-folders containing the edits, ones I am working on [or planning to], and ones that I plan to delete, but want to make sure first by looking at them again a couple of times at intervals.

The problem with deleting the originals, is you are risking the possibility that you will delete the version that is based on that original, which means the original is now gone. Even with backups, you may still not be able to retrieve that original. I don't know how your backups are set up, mine are for "mirror" so that changes in the master folders on my hard drive are reflected in the external hard drive backups. I do have one backup that includes everything, no changes, but that can fill up a drive very quickly. I only do that as insurance, on a 4TB external hard drive - and periodically I will switch that to mirror to clean it up, then back to full backup.

The only things I delete are those .xmp sidecars, but only after I have either decided I don't need them any more, or after I have converted them to .tiff. Having those little blank page icons on my hard drive is annoying to me, because I want to SEE those images!

Hope this helps.
Susan

If I understand correctly, You copy your photos from camera to computer folder(a). Import through LR to Computer folder(b). Then PP photo in LR. You didn't say Raw or Jpeg files, but in either case LR does NOT make changes to either. Changes are stored in the database and sidecar files which are stored in computer folder (b).
When you export files to external drive(a) from LR the export option dialog window has an option to copy the original files & the .xmp file to another drive (Raw or Jpeg). After cop you will have the original unaltered file stored in 3 locations.
bottom line: You can delete the images from computer folder(a), I would NOT delete any files once imported into the LR locations, computer folder(b) or external drive(a)

My work flow is: open LR (I use Classic). Under File select New. Enter the new folder name and select the destination drive. When LR reopens with the new folder name I select Import and plug the chip into the reader and import the files contained on that chip. Under File is a selection “Export Catalog”. I use this to save the folder to a different drive as a backup using a version of the catalog name modified by adding a number 1 to that name. I can then delete any unwanted images noted when initially surveying the images.
After processing an image I then right click on that image, select “Edit In” then select “Smart Object in Photoshop to complete processing, save as a specific file to the drive of my choice. I make jpegs in Photoshop as well.
I have saved the files to two different drives, saved specific images via Photoshop and made jpegs for sharing in a few moves.
I also save chips that contain valuable (to me) files.
Hope this helps!

You probably want to use <quote reply> to respond to specific individuals.

When I started with LR, I too thought just the final results were relevant. But, I learned it's the original and the LR "engine" that are the key components, more so than the result. Using the LR Export process, you can always generate the processed result whenever desired and into whatever format needed. But, if you've deleted the original, you've greatly limited your options to change the image, should you have a new need and / or new techniques or skills in processing. I have images from years ago that I'd really like to reprocess. But sadly, I have only the processed and downsized JPEGs that exhibit my rather limited knowledge and skills used to create them. And my decision to delete the original has cut off my options to apply new technique and the power of LR on their processing.