the moss lasts about 2-3 days if your temperature is right, you just need to spray and soak it again and it will be just as good as new. i recomend changing the moss ever 3-4weeks completely. XX
im in the process of setting up and have also found contradicting 'care sheets' of location of the moist hide, i have a very large viv so i think i'll put mine somewhere near the middle reading these replies