Accuracy shifts with winding, wear time, position, and temperature, so judge it over several days, not a single reading.
A noticeable deviation on a mechanical watch is easy to misjudge from a single comparison. This list walks through what an owner can check without opening the case โ winding, wear, position, and environment, in that order.
The order favors what's easiest to check first, not importance. Don't rely on a single day's number โ log a pattern over several days, and use the last two entries to decide whether the watch actually needs service.
01
Log Daily Deviation Under Consistent Conditions
Comparing at different times with different wear patterns each day makes it impossible to spot a real trend. Compare against a reference clock at a similar time daily, and note wear time and position alongside the numbers.
02
Don't Conclude Anything From a Single Reading
Mechanical watches can vary day to day, so one number rarely tells the whole story. Track at least several days' average alongside that day's conditions.
03
Confirm It's Fully Wound
Low mainspring power can reduce amplitude and make the watch appear to run inaccurately. Follow your model's recommended winding method and count, and never force the crown.
04
Track Wear Time and Activity Level
Automatic winding depends on wrist motion, so a lightly-worn day can skew the reading. Flag low-activity days separately in your log.
