If you grew up testing food for doneness by touch, a meat thermometer may seem superfluous. But many good, largely intuitive cooks swear by their meat thermometers. They really eliminate the guesswork.
A probe thermometer can be inserted, set for the temperature you want, and the alarm will go off when the meat reaches that temperature, with no poking or pressing the meat by you. You can do other things around the house, with no worries.
Das Ubergeek likes the probe for pound cake, which can take anywhere from 2 to 2 1/2 hours, depending on the weather.
Poultry is tricky to get just right. Karl S. places the thermometer on the inside of the thigh near the breast meat.
An instant read thermometer is great for a quick test of temperature. With the probe type thermometer, on the other hand, you insert the probe in the meat or poultry at the beginning and you never have to open the oven until your food is perfectly done. The temperature display remains outside the oven. Here’s an example
SanseiDesigns says to be sure to calibrate a new thermometer so the temperature is true. This website offers more info, and at the bottom (in the sidebar) are instructions on calibrating, if it’s necessary.