Hi there
CS6 will work for YEARS -- also if you don't use all the CS6 features CS2 is available FREE on the adobe site as "Abandonware" - but grab it while you can. I only upgraded to CS6 because I use the extended version with 3-D support.
If you use CS2 --99% of CS2 is more than enough for non Pros (and even for a lot of pros too) then you can convert RAW files for unsupported newer cameras by simply using the CAMERAS own software to convert the RAW file to TIFF etc --then carry on working in photoshop.
It will be a long time --if ever before I pay Adobe a subscription to use Photoshop.
Link for CS2 software - includes PUBLISHED serial numbers --100% legit on Adobes OWN SITE
Adobe - CS2 Downloads
Cheers
jimbo
Getting off track for a minute, but...
One of the things that make people upgrade their Adobe products is the new versions of ACR (Adobe Camera Raw). If you have a new DSLR (Digital SLR) and shoot RAW, the older versions of Adobe & Lightroom may not support the camera's new RAW files - For Nikon those are .NEF, for Canon they are CR2.
Example, I have a Nikon D800E, and though CS5's ACR can read the NEF files from the camera, it is version 6.7, contrast that to CS6's ACR which latest version is 7.4 - upgraded features, better interface.
CS5 -
Adobe issues ACR 6.7 - final version of Camera Raw for CS5: Digital Photography Review
Lightroom & CS6 -
Adobe releases Lightroom 4.4 and Adobe Camera Raw 7.4: Digital Photography Review
So, you buy a new DSLR today, but your old version of Adobe is CS2, or Lightroom 2... guess what? They aren't going to support the Camera's new RAW format. So, you either have to upgrade, use the default (often inferior) software, or find something else.
This of course is for those of us who shoot RAW exclusively, which is the best way to shoot (DLSR) as the file can be manipulated much more easily without losing or destroying data. It is considered the "master" negative.
Anyway I thought I'd drop that bit of tid-bit in.