I have been tracking my BBT with a thermometer I bought at the drug store. It seems pretty accurate. It is very quick to take the temp, prob less than 10 seconds. I bought a new one just as a backup and tried it. It takes almost a minute to take the temp. I used both to compare and the new one is coming out at almost a degree higher. Anyone had this issue or why this might be. I am now tracking both sets on different apps! Talk about driving yourself crazy!