Zoomed, All Living Things, Exo-Terra, and Flukers... I use at least one analog and one digital at all times. I also keep a spare just in case I see my cham acting funny and I need to double-check my setup. A good Idea is to get a infrared heat thermometer gun. They are relatively cheap and off a real good accuracy when compared to most in-cage temp gauges.
I test several of them. For "serious work" is just Caliber IV. There has +- reliable relative humidity data metering + is min max. Al other were enough precise by temperatures but no way in humidity.