Crikey,,,,
What sort of houses do you guys live in ?
Where I am, I have never put anything like crystals, dehumidifiers etc in my safe, and have never had any issues with dampness.
Summer or Winter.
The house has concrete floors with carpet and tiles.
The walls are cavity brick.
The roof is galv iron over all steel trusses, and is well stocked with insulation.
All doors are left open with just the screen doors closed from sunup till sunset during our winter (which is our dry season).
And,,,,,,,,,,,,,, as I said, no dampness issues whatsoever.
I do not fear death itself... Only its inopportune timing!
I've come to realize that,,,,, the two most loving, loyal, and trustworthy females in my entire life were both canines.