If you Google these questions, you will find various answers.
- It depends on a few variables.
- No one (that I know of) has directly tested it.
There are no studies comparing identical watches – one stored in a safe vs. one stored on a winder – for a substantial length of time. If there were, the differences would most likely be negligible.
Having said that, I have done extensive research on the topic, and I can make some reasonable recommendations based on the facts.
This also brings to mind the debate on optimal service intervals, but that’s an article for another day. Let’s stay focused on the question at hand.
Should You Keep Your Watch Wound?
If your watch is relatively new (made in the last 15 years), keeping it wound will not make a noticeable difference in performance or longevity of the movement.
If you have a really old and/or valuable timepiece, and your main concern is preservation of the movement, then storing it and winding once every few months is ideal.
“Watches don’t need to be kept wound all the time, but dormant watches in storage should be wound each few months ideally in order to prevent oils from stiffening.” – Arial Adams, Founder of ablogtowatch.com
Continue reading for a better understanding…
Movements properly lubricated with modern-day synthetic oils should not stiffen. Also, the oils are not likely to move due to capillary action; however, they will eventually dry up.
“…the synthetic oils will dissipate, and leave the parts dry, but this happens regardless of whether the movement is running – it’s really just a matter of time.” – Shane Griffin, founding member of Wound For Life – Opinion: Do I Need a Watch Winder?
You cannot over-wind a spring-driven automatic watch due to the preventative slipping mainspring. You can thank Patek Philippe for that.
“On June 16, 1863 Adrien Philippe is accorded Patent No. 58941 for the “slipping” mainspring. This invention allows simultaneous winding of two or more mainspring barrels, a technique which is the foundation for all further development of self-winding systems in wristwatches.” – Patek Philippe History – Collecting Watches
Sometimes an automatic watch will stop running at full wind, but this is because of a dirty movement, defect, lack of oil, or other damage.
“Watch movements, in particular, require regular cleaning and lubrication, and the normal result of neglecting to get a watch cleaned is a watch stopped at full wind.” – The myth of ‘overwinding’ – Wikipedia
It’s almost unheard of for a traditional manually wound watch to have a slipping mainspring. This means that they can be damaged if wound too tightly. Occasionally, some manual watches with power reserve indications will have slipping mainsprings. To be safe, stop winding if you feel extra tension.
“After decades of use, mainsprings in older timepieces are found to deform slightly and lose some of their force, becoming ‘tired’ or ‘set’.” – ‘Tired’ or ‘set’ mainsprings – Wikipedia
This is hardly a reason to keep a modern watch un-wound, but it might be a consideration in an extremely valuable vintage timepiece. For example, Albert Einstein’s watch, sold at auction in 2008 for $596,000.
Also, some would argue that the mainspring is not crucial for originality. Much like replacing the tires on a car, replacing the mainspring can help maintain original performance (without impeding other functions).
Wear and Tear
Damage due to use is real (shock, wear on screw down crown threading, magnetism, exposure to water etc.). But if you buy a well made modern watch, and you’re not cage fighting with it, the movement should be fine. It was made to run and stop, without doing damage.
At the end of the day, it comes down to your needs. If you have an expensive perpetual calendar, a watch winder makes sense in terms of convenience; and you’re not doing any damage to the movement by keeping it wound.
Conversely, if you have a valuable watch that you would rather protect than wear, storing it and winding every few months is your best bet.