For a Swiss chronometer certificate, tolerances in time keeping for a mechanical watch is an average daily rate: -4/+6  seconds.
Quartz watches Average daily rate at 23 °C: ± 0.07 second.
Mechanical watches: "I over-wound my watch"
Quartz watches: "My watch stopped it probably needs to be serviced"
Water resistant watches testing: "How deep can my watch go?"
Question and Answer:
You alone should decide whom will perform the necessary Regular Servicing on your mechanical watch when needed. Any mechanical watch should be serviced between three to five years.
Therefore when purchasing a fine watch make certain that parts you may need for these services will be available to you or the watchmaker of your choice.
Don't place your-self at the mercy of any brand. This will leaves you facing the reality when a servicing will be needed: Pay or Discard your watch!!!!
- Copyright © Andre Fleury – Swiss Watch Company Co. All Rights Reserved
Your watch stopped because the mainspring did not unwind for mechanical reasons.
Mechanical watches need regular servicing, there is a lot of friction, oil and grease has to be fresh.
Therefore your watch must visit your local watchmaker's between three to five years.
Your watch may just need a fresh cell. Quartz watches have a floating gear system, therefore no friction. If after replacing the cell your quartz watch does not keep proper time then it is time for servicing. Servicing is not necessary each time your cell is replaced.
For the recreational diver on air, the limit is 130 ft.~ 40 meter.
For helmet air supplied commercial diver 200 ft. ~ 70 meter.
For gas helmet diver 300 ft. ~100 meter.
Therefore if your watch pass a water test to 100 meter you qualify as an open sea commercial diver.
Andre Fleury Swiss Watch Co.
Quality and Service since 1968