Under certain circumstances, a watch may not be as accurate after a repair as it was before.
repair, the rate of the watch movement is checked using a timing
machine and by observing its behaviour over a certain period of time.
This usually takes place at room temperature and with simulated
sequences of movements. However, on the wearer's arm the conditions may
be completely different, which would result in the rate being different
than during the test after repair.
best thing to do is to look out for deviations and note down how fast
or how slow your watch is each day. Your watchmaker will then regulate
the watch according to the information you give him. Under certain
circumstances, it may be necessary to repeat this step, but in the end
your watch will be set perfectly to your personal lifestyle.