(a thread like this was the first I ever encountered on MN and I cried with laughter and relief. So can we have another one? It's too long ago to be able to find and resurrect..)
You know you have an SN child when...
..everything in your house is getting higher and higher in order to keep it out of harm's way.. so high that even poor-little-short-DH can't reach some things...
.. your storage cupboards are fixed together with hair bobbles...
..you have a whole filing cabinet devoted to the your SN child's various reams of paperwork...