Tiffany normally never has sales and I have never seen the freestanding boutiques have a sale.
HOWEVER, there was the confirmed 25% off yesterday at the Tiffany boutiques inside Holts in Canada. I've never seen this before and am kicking myself for not going since Tiffany has always been excluded. It's been confirmed though that Tiffany for some reason was included. If it makes you feel any better, the Tiffany inside Holts only has a limited selection, mainly silver items. My DH would have killed me if he could have bought my e-ring and wedding band for 25% off I bet!!