I am thinking of installing one in my safe, and would like to know how difficult is it?

Also how recommended are they?

I keep the air in my house dry, Centrel heat/air, the safe is in a dry location, steady temps. Would I even need one?

Thanks.....

In my house, I'd only put a Goldenrod in a basement safe.

You need to figure out just how dry or moist your safe location is.  Even a cheapy Walmart $5 thermometer/humidity gauge combo will tell.

I have about 75% humidity in my new homes basement, which was enough to start rust whiskers
sprouting on my SKS, even with a Goldenrod.  I now run a dehumidifier down there, to keep the
whole basement around 50% humidity.

They are easy to install.  Just use a metal drill bit and drill a tiny hole, just  big enough to get the electrical
cord (without the plug attached) through.  Once it's through the hole,, the plug that comes with the Goldenrod has a feed through hole that you just stick the cord through, you simply squeeze the two electrical wall plug prongs together (they have little teeth that "bite" into the cord, making contact, no soldering or twisting wires at all) , this clamps them to the cord which you ran through the hole.

Some people use a low wattage bulb, and say it works just as good.  I've had a Goldenrod running
3 years straight though, that would have been a few bulbs already.

I just read a big thing on this that come with my safe and it basically said what others are saying : central heat and air = NO golden Rod , garage or unheated = YES Golden rod .

What is the ACTUAL humidity?  I measure mine.  Humidity can get high in AZ because of swamp coolers.  

The goldenrod installs in minutes.  It is a small wattage heater and heat rises. Put it on the floor.  It comes with two clips that are installed by a couple screws.  It is fairly easy to drill a hole in a safe to run the wire.  If you need to cut off the plug to feed the wire through a 1/4" hole, do so and install a new quick-install plug.  I don't remember if it came this way.  

It is cheap insurance.

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I've got an 18" golden rod in my 14-gun Sentry safe...However I also have a humidity meter from a pet store inside my safe, but it reads normal outdoor humidity levels. My GR feels warm to the touch. How come it's not working/reducing humidity? Thanks!
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Quoted: don...seal your safe door with self-adheasive foam-backed weather stripping. mosts safes breate too much to suit me. add a second seal to the door and silicon caulk your power cord hole and eyebolt hole.

Yes, this is what I also have done and placed a container of silica gel inside, no problems at all.

I difinitely recommend it, and so long as your safe has a hole to thread the power cord through, it's rediculously simple to install.

You may have to splice the power cable inside the safe, but that's it.