[eddym]

Does anyone know how much a lens can endure before it gets fungus rot? I am not a highly technical person and I want to protect my camera lenses and microscopes too!

Not much. Again, at temperatures over 80F and humidity over 50%, it doesn't take long for fungus to begin to attack the glass. If you catch it early, you may be able to have it cleaned fairly successfully. But once it etches the glass, there's nothing you can do. I lost some nice lenses to fungus before I got my dehumidifier.