I’m not a fan of Goldenrods because they are constantly drying. If your safe gets too dry, gun stocks can crack.
What is too dry? My research has shown that ideal humidity should be between 40-50%. That’s not set in stone, just ideal. If you go a little bit above or below you will be fine. I have small AA battery operated temperature/hygrometers by Accurite in each safe. They are under $12 at Walmart.
Everyone’s situation and climate is different. A Goldenrod MAY be fine for my safes in the garage, I live in a humid area. But I wouldn’t consider a Goldenrod for safes in the house since I have climate control (central heat and a/c).
As far as dehumidifiers (DH) go, I have tried a few, and have found something I really like now.
The old metal canister DH are a PIA. Whenever the lame color code card changes from pink to blue you put the canister in the oven for 12-14 hours at 200 degrees. Very similar process with the bag type DH as well. Besides the inconvenience, the lame color cards “die” quickly and don’t last long. This is another reason for the hygrometer.
Now this Eva Dry DH is pretty good, but multiples are needed for a large safe and they “Fill up” too quickly. It seems convenient on the surface that you just plug it in to reactivate it when the beads turn green, but it takes 10-12 hours.
I prefer this Eva Dry because it holds more water and thus lasts longer. Also, since you set it on a warm blower to reactivate it only takes 1-2 hours.