For all those new to incubation, I wanted to tell you that the thermometers that come with bators are notoriously inaccurate. They can read as much as 2 degrees off sometimes, completely destroying your eggs. Temps are much more important than humidity. Humidity can vary quite a bit, but not those temps.
This is one of those things you learn the hard way of you dont hear it first or fail to heed the warning. Cyn is right; my first bulb thermo blew up in the bator!
I ended up with remote probe, digital aquarium thermos. I check them against infant thermos for accuracy, since they are warranted to be accurate to within .1 degree.
As for hygros, I have never had one that was far off enough to matter. I currently use one made for cigar humidors. Humidity is more of a range thing, but temps need to be dead on. Good conscientious post, Cyn.