What goes up must come down, and since most of the world has yet to go up from the 2008 crash, I'd say we're a good decade away from having to come down again.
Didn't the US sink into another recession in 1938 after some years of growth in the immediate great depression era ?
This was discussed at length in another thread. I believe King's official position was that it was caused by a completely misguided tightening of the money supply - something that makes sense to most but can be disputed. I tend to fall into that camp myself at the moment, but I'm not sure it was the sole cause.
It appears the Fed will continue to push off such a solution further and further, but I wouldn't be shockey if it happened again. I doubt it would be nearly as severe though.