I have 2 of everything, with 2 hose reels out the back door.
when 1 pump went down, we used 1 pump to 2 reels but found whilst it worked ok, it did favour one hose over another, I think as p and f said, if you have 2 then you've always got a backup as well.
no pix to show, will try to update later on laptop.
oh, and we do house each if possible, ours are typically 3 bed semi in housing estates. or can do front and back if big enough.