Our watches are exposed daily to various magnetic fields. Depending on their intensity, these fields may put your watch out of order by altering the timekeeping. Magnetic fields can stick the hairspring together, and as a consequence, the watch could slow down, accelerate, and even stop.
Despite all the care brought by Watch-making brands, repeated or very long contacts with a strong magnetic field may affect your time-piece. Leaving your watch every night close to a loudspeaker or an alarm clock could for instance magnetize your watch. Therefore, whenever possible, rather steer clear of these fields.