The duration of all harmful Magic effects used against you is reduced by 25%.
Armor Spells A Mage can only have one Armor spell active at a time.
Mage Armor is a core mage ability learned at level 80. It is a self-only buff that improves your mastery; in addition, the duration of all harmful Magic effects used against you are reduced by 25% when Mage Armor is active.
Use: Permanently teaches you this glyph. Reduces the cast time of your Frost Armor, Mage Armor, and Molten Armor spells by 1.5 sec, and increases the defensive effect of each Armor by an additional 10%.
Sell Price: 1
This is very handy in groups and on raids when you're not being hit, but your ability to keep fighting over a long period of time is important.
Unlike Frost Armor, this will not slow your attackers, so don't leave this up when running through a dangerous area.
In PvP the 25% debuff time reduction can be a life-saver, especially when facing Warlocks, since a great deal of their damage comes from damage over time effects and dispellable curses.
Patch 5.1.0 (27-Nov-2012): Mage Armor now reduces the duration of harmful Magic effects by 25% (down from 35%).
Patch 4.0.6 (8-Feb-2011): Now reduce harmful magic debuff's duration by 35%. Down from 50%.
/Patch 4.0.1 (12-Oct-2010): Now restore 3% of total mana every 5 sec, instead of granting a spirit based regeneration.
Patch 3.1.0 (14-Apr-2009): Now grants 50% of mana regeneration while casting. Up from 30%.
/Patch 3.0.2 (14-Oct-2008): Frost Armor, Ice Armor, Mage Armor, and Molten Armor are no longer Magic effects and cannot be dispelled.