I have always used the accurite digital thermomter/hygrometers in my incubators. they have never been really accurate, but I was manageing to have pretty decent hatches. Recently, my last two bunches of eggs had very poor hatch rates, the last batch a zero hatch. It seems that my hatches where getting later and later about hatching, some taking 23-25 days to complete and a lot of non-hatchers. Late hatches is usually a sign of to low temps, but I was compareing several different thermometers and thought I was in the correct range. I actually raised the temp setting to 100.5 to try to get back to the 21day hatches. One cheap themometer would always be about 5 degrees low. I am starting to think that the thermometer that I thought was off the most is probably the only one that is really close to being correct. Anyways, I am ordering a couple of the spotchecks thermometers and will try another hatch after they arrive. I know several here seem to really like them. I would really like some feedback on the accuracy of the spotcheck thermometers as well as info on just how long the battery really lasts. Brisnea's website say 6 wks, another website says six months. Also are the batteries easy obtainable locally or do you have to order the batteries everytime they need replaceing. I will order a couple of extra batteries when I order the thermometers, but if I have to keep ordering the batteries and paying shipping everytime I need a batttery, I might just try finding some other thermometer to use instead of the brisnea.