I live in Darwin where the humidity hits the high 90%, I have heard of people investing in those de-humidity cabinets and the like and at one point looked into buying one myself. I have heard that the best way to avoid fungus is buy subjecting your lenses to sunlight ie. take them out and use them regularly. I am generally careful when going from airconditioned environments to outdoors so that condensation isn't a problem - in this case I keep my gear in the bag for about 1/2 an hour so that my gear isn't subjected to the quick changes in temps (condensation). This is all I have done other than keeping my gear clean and dust free and although I have only had it for 2 years I have not had any problems with fungus. A friends husband who is a tog had to replace heaps of his gear and his is kept in de-humidity cabinets - go figure