Digital BW, The Print

when you sell your "carbon pigment" prints (MIS or Piez), what claims 
can you safely make regarding the archival issue. 

How long can you safely claim the print's integrity under 'normal" 
hanging conditions in a home environment (which I'd say is a fair mix 
of ambient(uv) & artificial (mostly tungsten) light.

Dark storage, pollutant free, humidity controlled environments are, 
of course, a little different.

I realise this would be specific depending on which paper has been 
used; but I'm just looking for some guidance- or a ballpark range.

thanks 
frank