I store lenses, cameras, prints, negatives, everything but wine and spirits in a closet in my darkroom. I have a dehumidifier to maintain RH below 50% and an air conditioner to maintain temperature below 80F. But then, I live in a rain forest. We also keep a dehumidifier in our clothes closet.
One exception: when drying FB prints after processing, I turn off the dehumidifier and allow the RH to get up to the 60% range temporarily; otherwise the prints dry too fast and unevenly.