I reckon he's got 18 months to 2 years, and Broad probably the same. I'm not looking any further than that at the moment, 2 years ago the first test against the west indies featured Trott, Bell, Tredwell, Buttler and Jordan, so anything can happen in that time.
I think Woakes will eventually replace Anderson as our number 1, and Wood will be a first choice if he can stay fit. Plus there's TRJ, the 4 Currans and Overtons coming through, and we're going to start hearing about Jofra Archer at Sussex a lot more soon, I'm absolutely certain, although he could do with getting into div 1 sooner rather than later. I'm actually far less worried about Jimmy retiring than I have been for ages, although it will still be a sad day when it happens.
Steve Finn exists too, although I don't really know where I stand on that at the moment.