Household thermometers are not meant to be as accurate as incubation requires. They can be up to two degrees off and still be acceptable for the market, I've read. AcuRite with probe is just typical household thermometer that may be semi-accurate the first time you use it (or not) but since you must place the entire unit in the bator to read humidity, the inner workings can become waterlogged and you have to remove the battery and leave it open to dry out. It's not meant for that type use. I've had two of them. One completely died after some use and the other one is slightly off, but I put its probe in a plastic egg filled with silicone to make my own egg-o-meter and it works pretty well, though this last time, it's had some off readings.
Spot Check is awesome and highly accurate. It's also sold under the name "Egg-Temp" by GQF. I killed my first one (my fault) and bought another because of the accuracy.