Recently on Caravan Talk someone was complaining about the floor creaking on their Unicorn 3.
It was suggested that checking the tightness of the screws that hold the furniture to the floor may be be a good idea and perhaps check it once a year or so.
Although we don't suffer from more than the odd squeak I thought I would give them a check and was surprised how slack some of them were,whether they were left like that after construction or have worked loose I don't know.
Anyway a few minutes with a screwdriver and all done so it may pay to check them over now and again.
Incidentally it is not until you stick your head into bed boxes whilst ferreting around for screws to tighten that you realise how flimsily put together caravans are,on the plus side though I didn't see any damp.