When I resize the buffers via IDXGISwapChain::ResizeBuffers(), it is required to release any references to views to the back buffer. That of course makes sense, because the back buffer texture is about to be changed.
But nothing mentions whether I should change the depth/stencil buffer at the same time. I'm guessing it's not a requirement because D3D can scale before outputting, but is it a good idea anyway?
Although you don't strictly need to resize your depth/stencil buffer, you will need to do so if you want to use it in conjunction with the back buffer render target. This is because the depth/stencil buffer must match the size of the render target. If you are doing deferred rendering, or some other technique that doesn't require a depth buffer bound when rendering to the back buffer, then you can omit the resize; but otherwise you should resize both to match the new window size.