The weakest parts of a wristwatch typically vary depending on the watch's design and materials. However, the following components are generally considered the most vulnerable:

1. Crystal (Watch Glass)

  • Material: The crystal covers the watch face and can be made of sapphire, mineral glass, or acrylic. Despite sapphire's durability, all crystals can be susceptible to scratches, cracks, or shattering, especially if dropped or struck.
  • Weakness: The edges where the crystal meets the watch case are often the most vulnerable to impact.

2. Crown

  • Function: The crown is used to set the time, date, and wind mechanical watches. It sticks out from the case and is often exposed.
  • Weakness: Since it's a moving part, it is susceptible to damage from impact, bending, or pulling. Water can also enter the watch if the crown is not properly screwed down or has worn seals.

3. Strap or Bracelet

  • Material: Watch straps can be made of leather, rubber, or fabric, while bracelets are often metal.
  • Weakness: Leather and rubber straps can wear out, crack, or tear over time, especially with exposure to sweat, water, and environmental conditions. Metal bracelets can break at the links or develop scratches, and the clasp can also weaken or break.

4. Pins or Spring Bars

  • Function: These tiny parts connect the strap or bracelet to the case.
  • Weakness: The small spring-loaded bars can bend or break, especially under stress from wrist movement or if the watch is caught on something.

5. Movement

  • Material: The watch movement (mechanism inside) contains many delicate parts, such as gears, springs, and jewels.
  • Weakness: Shock, magnetism, moisture, or dust can disrupt the movement’s accuracy or damage these components. Even automatic movements are sensitive to rough impacts or improper servicing.

6. Case Back

  • Material: The case back protects the inner workings of the watch.
  • Weakness: If not properly sealed or if the gasket wears out, moisture or dust can enter, affecting the watch's water resistance and movement integrity.

7. Gaskets and Seals

  • Function: These are critical for maintaining water resistance in the watch.
  • Weakness: Over time, gaskets can dry out, crack, or lose their effectiveness, compromising water resistance.

8. Hands

  • Function: The hour, minute, and second hands are delicate components that indicate time.
  • Weakness: These can become misaligned, come of or be damaged due to shock or improper handling during servicing. The most vulnerable hand of the three by far is the secondhand because it's much smaller and finer than the other two watches with tritium GTLS tubes are also more prone to issues with the hands due to the weight of the tube.

9. Bezel

  • Material: On many watches, especially dive watches, the bezel is a rotating or fixed ring around the crystal.
  • Weakness: Bezels, especially rotating ones, can wear out or become loose, and if not properly aligned, can trap dirt and dust.

10. Lume (Luminescence)

  • Function: This is the glow-in-the-dark material applied to hands and hour markers.
  • Weakness: Over time, the lume can wear out, lose brightness, or degrade, particularly on older or poorly maintained watches.

Conclusion

Each part of a wristwatch is critical, but certain areas, like the crystal, crown, and strap, face more external wear and tear. Regular maintenance, careful handling, and avoiding extreme conditions can help preserve the integrity of a watch.