As I said in the PM I sent you, stop opening new threads. That also means use the edit function and stop "bumping" your threads. You are not the only person here with an issue. Relax, breathe. Everything will be ok. You'll get this done and everything will work out. No need to open 8 threads on this subject, or bump your posts so it's always at the top. Keep in mind today is Sat and people are out enjoying the weekend. You'll need to wait more than 18min to get answers sometimes.
How long will the CIT last? We have no idea. It's not the worst unit out there so it might last awhile. You might live in an area with horrible power spikes and it's on it's last legs. How are we to know? Assuming "normal" things like you haven't abuse the PSU and kept the temps down and you have normal power delivered to your house, I'd expect that PSU to last "normal". It depends on how long you've used it, how hard you've used it, and how cool it's been kept. We have no idea on any of these. The safest thing to do is to buy that CX PSU. If you lack the extra £6 it's up to you if you want to risk your rig.
Edit: The VS is considered worse than the new CX models. The VS series is similar to the old CX models, but with better efficiency. The new CX series has better internals that can handle things better. I'd take the new CX over the old VS.