Well, your ORIGINALS remain unchanged. If you drop your Lr subscription, you can still export from Lr with previous stored changes applied.

Software companies are not legally allowed to prevent you from using your data — and they would be stupid to do so, anyway! Your previous edits are accessible, but no changes can be made until you resume paying your $9.99 per month for the Photography Bundle of Lr, Lr CC, Ps, and Br.

Lots of people panic, thinking Adobe is ransoming them or something by charging subscription fees. That's crap. People with the previous Lr 6.x stand-alone version can keep using it until it is inconvenient to do so (meaning their computer OS won't support it any longer, or they need a new feature that wasn't in the original, such as support for a new camera raw profile).

Since I need both Ps and Lr CC, I subscribe. I've used Ps since version 1.0 back in the late 1980s. I used Lr since the first beta test.

I used to skip every other version of Ps, because the Adobe upgrade fees were too expensive. I couldn't afford $300 to $400 for a Ps upgrade, but I can afford $10/month. That's a decent bottle of wine, two or three Starbucks coffees, or four gallons of gas. You can't even buy a roll of film and processing that cheap, these days (That's about $30 if you want prints!).

I've said this before: Digital photography is an expensive hobby. By the time you get the equipment to do it right, a $10/month charge for software licensing is cheap, cheap, cheap! I have a small setup:

iMac $1200
Backup drives $1200
Network infrastructure $550
100Mbps Network access $50/month
Monitor Calibrator Kit $150 (The single most important tool I own!)
Desktop Printer $150
Photo Printer $400
Lumix GH4 $1300
Three lenses $1700
Other items (tripod, flash, filters, case, light stands, exposure targets, shoe mounts, LED lights, memory cards...) about $2000

So another $10 is not a big deal.

Most sources on Adobe say that once you cancel your subscription, you can still access the Library module of Lightroom and can export your edited images from there, but you cannot access the develop menu to do further editing or add other images. There are a few editing options in the Library module, as you can see, but not many.

That said, if I were planning on discontinuing LR I would export my images as TIFFs and hang onto them myself, as Adobe could change its mind about their option at any point.

Legally, Adobe cannot block you from accessing your images the way they were developed when you were a subscriber. And from a marketing standpoint, the evil in that would be so heinous it would not survive public shaming. All they do is prevent you from making additional changes. But you can re-subscribe and do that.

I do agree that exporting images as TIFF (and probably DNG as well, to preserve the raw data), would be advisable. It makes it easier to use your images in other applications.

It's important to note that Adobe's growth since the advent of their Creative Cloud subscription plans has been substantial! The overwhelming majority of customers prefer low monthly payments for an always-up-to-date version, instead of one lump sum for a fixed version that requires a fee to upgrade.

I connect camera to my Mac and 'copy' images across into My Pictures folder and LR Classic.
I then sort , delete, edit etc etc.
If/when I delete I choose the Delete from Disk option to remove them from my LR Catalog AND the My Pictures folder on my hard drive.
When exiting LR I choose to backup each time.

If I leave the subscription though I think (?) my photos in My Pictures folder and the backups in Time Machine and Carbon Clone (both done daily) will not be 'the same' as those I view in the LR catalog/library?

Am I correct and what is the solution so that I know I have the edited images safe and sound on both my Mac and my external HDs please?
Do I have to LR export every photo to the appropriate folder in My Pictures?

Many thanks in anticipation.

Most sources on Adobe say that once you cancel your subscription, you can still access the Library module of Lightroom and can export your edited images from there, but you cannot access the develop menu to do further editing or add other images. There are a few editing options in the Library module, as you can see, but not many.

That said, if I were planning on discontinuing LR I would export my images as TIFFs and hang onto them myself, as Adobe could change its mind about their option at any point.

Many thanks Bobhartung and SusanfromVermont and everyone else - all much appreciated.
I am not thinking of cancelling at all......and rightly or wrongly think the sub represents good value to me/for me at this time....also challenges my ageing brain cells working on LR/Photoshop so a double bonus.
I'll go down the Format/Export route from here on in...so that I too have a back-up copy of the edited file as well as the LR catalog......with the price of data storage being what it is....tis well worth a few pounds to have the photos....original and edited.
Many thanks again All.....:)

Glad my comments have been helpful!

I cannot emphasize enough the value of having a backup of the original photos file on your hard drive. This means an additional external hard drive or even two more. If your single hard drive should fail, you need to have that backup so you do not lose your images. The reason behind this is that it is not a question of IF a hard drive will fail, it is a question of WHEN! And this is true of both internal and external hard drives. Never believe that it cannot happen to you. I have been doing multiple backups for quite a while, and never had a problem UNTIL I DID... For the first time, one of my 4TB external HDs died and it was less than a year old. The company replaced it [under warranty], but I would never have had my images again if not for other backups. [Apparently there are ways to retrieve information, but it gets expensive.]