I come from a work background that takes calibration very seriously. For the home or even typical commercial user, this type of scrutiny is unnecessary. However, I still want my equipment to stay accurate.

• What is a typical drift/time does the most popular products see (like the thermapen)?

• How often should I send in a unit for calibration if at all?

Feel free to get into as much detail as you want since this actually interests me. For those of you that may not realize, I used to work with VERY expensive temperature monitors. Not only did we have our measuring devices calibrated every year, the spool on which we made our thermocouples also needed to be tested. When we submitted our reports, we would have to take into account the deviation of the device and the deviation of the thermocouple wire. This was provided as part of the certification in a tabular form with the range of temperatures they were tested at. I've seen drifts as much as 7°F between the expensive measuring device and the new spools thermocouple wire combined.