I installed a Thermidistat in my condo about 17 years ago and maintain a relative humdity of around 52% which allows me to keep my instruments in a rack and hanging on the wall where I can easily get at them. I live in South Florida on the edge of the Everglades and we experience exterior humidity of 100%, or close to it, about 7-8 months out of the year it's a major concern but so far no problems.