Game Description: Occasionally reduces spells' MP cost.
Job Traits are always active.
The Conserve MP trait obtained at Black Mage level 20 is a "Conserve MP +25"; it activates for approximately 25% of spells cast. Equipment that gives "Conserve MP +X" increases the activation rate of Conserve MP by approximately X% of spells cast. E.g. Conserve MP +5 in combination with the Conserve MP job trait will give a net activation rate of 30% of spells.
When Conserve MP activates, the cost of the spell will be reduced to n/16 * (original cost), rounded down, where n is an integer ranging from 8 to 15. All possible values of n have an approximately equal chance to occur.
With a base activation rate of 25%, Conserve MP allows you to retain approximately 7-8 MP for every 100 MP spent. The actual amount retained may vary.
Conserve MP will not allow you to cast a spell for which you would otherwise have insufficient MP to cast.