Quote Originally Posted by The_NPC View Post
From what I saw when I was rebuilding hotbars for my PLD during EA (don't have xpac yet waiting till payday) my one i270 ring had 57 Tenacity on it & temp-removing it dropped my DEF/MDEF by 1 so I assume its roughly 50 Tenacity equalls 1 point of DEF/MDEF (& probably around same in DMG as it affects that too)

Dont' see Tenacity being too good unless u stack a crap ton (Like its on each gear slot giving around 60-ish each) as at end-game 1 eaxtra point of DEF/MDEF isn't much, its something thou which makes it better than what it replaced (Parry)
Just wanted to say that your DEF/MDEF probably dropped by 1 because the i270 accessories give +1 DEF/MDEF.