Which is better?

A: Many people believe that Mercury free Glass Thermometers are superior to digital ones because they are more accurate.
However, there are also several advantages of a digital over a glass thermometer: 1. The first advantage is speed, the BBT digital thermometer takes 30-60 seconds (as compared with 2-3 minutes for a glass thermometer). Even though this is a small difference, it can matter if you have to go to the bathroom first thing in the morning. 2. Many digital thermometers are more durable and less likely to break. 3. Some digital thermometers also keep your last temperature in memory, this may be helpful when you do not want to write down the temperature right away. 4. Digital thermometers do not have to be shaken to bring down the temperature.
Glass thermometers need to be brought back to a low temperature, and this is usually done by shaking the thermometer. It's not suggested to move a lot before taking your BBT, so if you forgot to do this before you went to sleep, shaking the thermometer may make the reading inaccurate.