Quote Originally Posted by walkerwek1958 View Post
Why do you see 100 metres WR as essential? I’m interested to hear the logic behind this.
I'm amazed you of all people are asking that question! Surely you're aware - for all the claims of watertightness to multifathom depths - that there is often a disjunct between that nominal figure and recommended usage according to many manufacturers? So extreme is this, that the manual for a 50m rated watch I briefly owned by "a major Japanese manufacturer" advised me that I should remove it in the shower! They are very likely just covering their arses, but it hardly inspires confidence.

There are other factors beyond immersion - heat, extreme cold, soaps, surfactants, solvents, acids, alkalis, pollutants, chemicals, salt, sweat, &c &c can all make a nonsense of some kinds of sealing and you can multiply that by time and neglect! And what of things like power-washers and dental water-picks for example? Localised pressure can be pretty intense...

Personally: the reason, as should be obvious from that list, is I like tool watches - watches that are tougher than I am, preferably overengineered to Brunellian levels. Overspecified? Gimme! GIMME!!!