Just finished building my new machine and currently have no editing software installed. I have copies of lightroom 4 and photoshop CS4 which I have been happily using up until now.
Lightroom is my go to program which I use for everything, Potatoshop gets used very infrequently. Am I going to see any real benefit for my £8.57 a month?
No.
You have application software that as you pointed out, you have been "happily using", and if they are still working fine with your current machine, then why replace them with updated ones? You know what they say:
If it aren't broken, don't fix it.
I have a 64-bit Windows 7 Professional Edition on a AMD FX6 machine with 32GB,
but I actually still use Microsoft Office 97 which I installed on my current machine and still use it to type up letter, memos, reports, and many other stuff with MS Word, also using Excel for records, and even using Access for database. I'm doing fine, no problems there.
Who says you can't use bows and arrows just because in the modern world, we use guns and bullets?
Feel free to upgrade if you wish, but why bother? Unless you really need some of those options that LR CC and PS CC have, which you really need to use, then by all means, upgrade.
Plus your LR 4 and PS CS4, they are fully paid for by you, and you can use them even if your computer is offline.
Whereabouts with LR CC and PS CC, you have to rent it every month, plus your applications need to check with Adobe that you did pay your membership, so you can carry on using it. Fail to pay your monthly costs, your application software gets locked or limited until you cough up the monthly fee.
Any real benefits in paying £8.57 a month depends on if you do actually use any of those new options that your current LR 4 do not have. If you don't use this menu, this option, this setting that LR CC have, which LR 4 do not have, then you may as well have stick with your LR 4, but if you do use what LR CC have, then it would be of some benefits to you.