What watch suits the outfit?
Dress Watches: A watch with a plain white face and no complications and a black leather band is as formal as it gets. The most formal dress watch are the ones that only show hours, minutes, seconds and maybe the date.
Diver's Watches: Designed for underwater diving, these watches feature a minimum water resistance up to 100 meters. Don't be inspired by James Bond movies and wear a divers watch with a suit. That's the equivalent of wearing a suit with work boots.
Chronograph / Sports Watches: Not a true dress watch, but can be quite dressy especially in the higher brands.
Pilot or Flyer Watches: Featuring a simple dial design and a rather large (over 50mm) diameter, these watches were made to be accurate and easy to read.
Field Watches: Are versatile timepieces that are tough enough for active duty. The simple design improves legibility of the numerals.