That is a good question, we recovered our cushions with fabric all around so we would be able to flip them and rotate them for even wear.
We noticed on our last few nights that there was a fair amount of condensation under the bed cushions, what we don't know is if it is always like that or just because it was a wet day.
All we did was flip them up and they dry in a couple of hours, but if you have a permanent 1 piece matress, that might make it a little tougher.