iBoss
i-ttack the space
You don't, but we should be looking to have a world class centre back. Terry and Cahill are a very good partnership, but that doesn't mean that Chelsea shouldn't be constantly looking to improve if they get the opportunity. Terry/Cahill are also bolstered by the fact that they're managed by Mourinho - it's no coincidence that they've been excellent since his return.
Not to mention that Evans generally isn't as good as Cahill anyway - if we can, we should be looking to improve upon him. Yes, you can't just go out and land lots of world class centre backs, but that doesn't mean you shouldn't try. If we want to become one of the best teams around again, we shouldn't be relying on Evans as our main defender. We had two world class players in Ferdinand and Vidic before. Why are we now lowering standards to the point where that's not what we should be aiming for?
If there is a WC CB out there available, we should buy him. I didn't say we shouldn't.