A watch winder is not essential for all watches, but it can be beneficial for specific situations, particularly for automatic watches and those with complex complications. For manual-wind and quartz watches, a winder is unnecessary as it won't wind them or help their batteries.

When a winder is helpful:
Automatic watches:Watch winders mimic the movement of your wrist to keep automatic watches wound and running, especially if you rotate through multiple timepieces.
Complex complications:If you have watches with perpetual calendars or other complex features, a winder can prevent the need to reset them each time you wear them.
Large collections:Winders can be convenient for watch collectors with many automatic watches, saving time and effort compared to manual winding each watch.

When a winder is not necessary or even potentially harmful:

1. Manual-wind watches: A winder will not wind these watches.
2. Quartz watches: A winder will not help the battery of quartz watches.
3. Continuous use: While some argue that continuous winding is beneficial, modern synthetic oils in automatic movements make it less necessary, and some argue that continuous winding can put stress on the movement.
4. Overwinding: Some winders may be set too aggressively, potentially causing wear and tear on the movement, says TaiHua.

In summary,While watch winders can be a convenience for specific situations, they are not a necessity for all watches. For automatic watches, especially those with complex complications or in large collections, a winder can be a useful tool for keeping the watch wound and ready to wear. However, they are not needed for manual-wind or quartz watches, and overusing a winder on an automatic watch could potentially cause wear and tear.