Before the watch can be timed, the following operations must be completed:
- pinning, centring and truing the balance spring
- poising the balance
- defining the count point
- possibly making a terminal coil
- pinning the balance to the stud.
The actual timing involves observing the watch in different positions and at different temperatures and making any necessary adjustments. There are different grades of timing according to the required degree of precision: ordinary timing, in different positions, at different temperatures, precision timing. Watches submitted to Observatories require high-precision timing. They are subjected to similar controls to those imposed by the Swiss ratings bureaux but results must fall within tighter limits and the tests last longer.