Many things have remained on my mind about this. The context is that I feel comfortable with the software I use now and I’d like to use it as long as I can without having to think about any changes.
One idea/question is this:
I now have my Lightroom catalog (still Lr CC 2015.6.1); Photoshop CC 2015.5.1; and my most important image files on my 1TB late 2014 MBP retina. Every day that I work I use Carbon Copy Cloner (CCC) to back up onto two external drives (two, to have built-in redundancy at my fingertips [I also rotate a third EHD that I keep in a bank’s safe deposit box]).
Thinking now that I might try Lr 6 perpetual license (buy the DVD and install it on my MBP using a new account), could I make a new clone of my current catalog and files onto a new EHD and upgrade only that catalog to Lr 6 while keeping the rest of my workflow (using Lr CC 2015.6.1 and Ps Ps CC 2015.5.1) as it exists now? That is, I’d have my current Lr CC version as well as the new Lr 6 installed simultaneously on my MBP and use each version only with its dedicated catalog and image files. Will that work? And if so in principle, what (if anything) would I need to clone to that new “Lr 6 perpetual license” external drive that isn’t in my Pictures folder? I wonder if I could just clone my whole MPB as it currently exists, upgrade the current catalog on it to Lr 6, and use it only for working with the files on that new drive. (I gather there would be some knotty problems with workflow continuity, but as I've thought about submitting this post I've come to believe I can handle them).
In truth I must admit to having no desire at all to have Lr 6 on a new perpetual license unless I knew that my current Lr version would for some reason come to the end of its useful life before Lr 6 perpetual would. Is this at all possible or likely? (See next paragraph.)
A related idea/question is this:
Acknowledging that some people are still using Lr and Ps under perpetual license (i.e, from pre-CC days); and that some people (I’m in this group) are on the subscription plan but for whatever reason don’t want to upgrade; and that others do prefer to upgrade within hours/days/weeks of an upgrade’s announcement, is it possible to know or reasonably anticipate any future hardware or software developments that would lead to one group’s "luck" (if that is the word) running out (i.e., they're no longer able to use their preferred Lr/Ps combination)? In other words, for example, would people still using Lr and Ps under perpetual license (purchased some years ago) have a greater chance of finding themselves “stranded” as things move forward before I would; or would they and I (assuming I never upgrade from my current Lr/Ps subscription’s versions) find ourselves stranded simultaneously while those using the new Lr Classic CC remain ok? And finally, given some of the recent (perhaps too highly imaginative?) prognostications I’ve read about Lr Classic CC going away a few or several years from now, if I committed now to Lr 6 perpetual license, is it possible to envision what might happen to make it no longer viable?