The collection I have is insured seprately to the house policy and valued individually. It costs more but, its worth it and, I am covered for the unthinkable 'accidental damage'.
The rest is probably what everyone else does keep them out of the sun I am fortunate the room I now have is only affected by the sun as it rises so, no problems there. Keep them dusted and cleaned and, thats about all I think you can do.
Mitch