Both longevity and sillage are in the low range. Not as bad as a mostly natural citrus cologne, but (in my experience) it is hardly noticeable without relayering, after somewhere between 2.5 to 4 hours, sometimes it's hard to tell. Its best bloom, both in terms of presence but also of quality is within the 30 to 90 minutes period after application. Remember that the slogan it's been launched with was "Royalty needs not shout". People won't necessarily notice Windsor or, when they do, might even think it's kind of "simple," which it most definitely isn't.
On advice from some BN-ers, I tried "over"spraying (which for me meant trying once five sprays of Windsor, which I never do with perfumes, except for Citrus Bigarrade or Bois de Cedrat or Eau de Guerlain). It became a lot more noticeable of course (and being of such quality it never descends into being insulting, like other oversprayed perfumes) but, you know what?, I did in fact not enjoy it better. I think that a certain discretion and subtlety is an intended part of the nature of this masterpiece, which I wear with great pleasure for myself rather than for the world.