Automatic watches are exceptional inventions that have stood the test of time. When purchasing an automatic watch, many important metrics are used to measure the quality of the timepiece’s movements.
How accurate an automatic watch needs to be will differ between different sets of wearers. Some people will need their watches to be extremely accurate. For example, professional divers or military personnel may require the most accurate watches, called chronometer watches. For those who care more about style and convenience, a standard automatic watch will be +-25 seconds per day.
This is a general rule of thumb regarding automatic watch accuracy. It means that an automatic watch should only gain or lose up to 25 seconds between two days. If a watch is gaining or losing more than 25 seconds in two days, then something is wrong with the timepiece, and it needs servicing.
BHP refers to beats, or ticks, per hour. Sometimes, watchmakers will use the terms beats per second or Hz. Most watches have a rate of six, eight, or ten beats per second, measured out as 21,600, 28,800, or 36,000 BPH, respectively. High-beat watches have a faster ticking movement. They are more accurate and precise since they read out smaller fractions of a second. The second-hand movements on a high beat watch will also appear smoother.
Fully wound automatic watches will have up to 42 hours of energy stored before they need to be powered again. In some automatic watch designs, they may house up to ten days' worth of power reserves.
Complications refer to functions on a watch that does something other than telling time. On many automatic watch designs, the timepiece may display the calendar date, moon phases, power reserve indicators, and also allow for alarm functions.
Automatic watches are reliable watch designs and are manufactured to be precise and accurate. Certain features can increase the timepiece’s reliability and accuracy, such as having a higher BPH.
Automatic watches typically have glass in the back so you can view the movement. Well-made movements make the time reliable, while poorly manufactured movements will have ticks that are inconsistently measured. Watches made with inferior materials can lose minutes in a day. Watches from Swiss, Japanese, and German movement makers are renowned for using the highest-quality materials for accuracy, precision, and reliability.