I live in an old house...most mornings I wake up up slug trains across the carpet downstairs or the odd dead woidlice on the kitchen floor. If I wake in the night I often see the slugs !! 
Tonight I happened to look out of my bedroom window to see about ten woodlice on the outside of the window ledge- which is plastic!!
I am slightly concerned here .. I thought they only stayed in dark damp places and typically wood?
The house suffers from rising damp- downstairs could there be an infestation in my walls??
Should I be worried here or am I over reacting!?