Advanced instance healing for priests The following is a guide on how to effectively heal to the best potential of your gear as a priest in 5 - man instances only . Some parts of this guide are not practical for raids and should not be brought into raiding , because you may let the tanks die , or simply do very little healing . The Basics . Gear . The first thing you should do before healing an instance , is to know what attributes are the most important and which ones you can neglect . Firstly , Spirit and spell - power are the two most important attributes for a holy priest . For a Discipline priest , spirit does not boost spell - power , reducing its effectiveness substantially , but not making it obsolete as an attribute . The reasons for spirit being such an important attributes to all healing priests and most healers , for that matter , will be explained in later sections . Secondly , Intellect and Mp5 are the secondary attributes for a holy priest . For a Discipline priest , the secondary attributes are Spirit and Mp5 . Finally , Crit rating and stamina are , while not the least important attributes , ( those being the useless ones , i . e . strength , agility , armor , attack power , and though not completely useless , resilience . ) are the least important attributes to stack , though are still important . Efficiency . Solo - healing as a priest , its important to think about Efficiency . Your job is to keep everyone alive , and not run out of mana . Spamming flash heals will keep everyone alive , but your likely to run out of mana very quickly on larger pulls or boss fights this way . The best way to stay efficient when not in an emergency situation , is to only use mana efficient heals . The heals that are mana efficient , are : Overhealing . Generally , as a healer , Overhealing is bad . But in the situation of a priest , due to the Serendipity talent , overhealing can be good , if you do it by a small amount . Ideally , you would overheal 1 % of your last healing spell of your wave , and regenerate 25 % of the mana spent for that heal immediately , leading to an overall increase in efficiency . Waves will be talked about further later in this article . The 5 - Second Rule . Instance Healing as a priest is all about cheating the 5 - second rule . What is the 5 second rule ? The 5 - second rule is blizzards line between while casting ( mp5 ) regen , and while not casting ( Spirit ) regen . Basically , when you finish casting a spell that Costs Mana , you enter IS5SR ( Inside 5 second rule ) regen . During IS5SR regen , you do not gain any mana from your spirit directly , though if you put some talents into discipline , you may gain 30 % of your spirit regen IS5SR from the Meditation talent . After 5 seconds , you enter OO5SR regen , which incorporates spirit regen in addition to your mp5 regen . Regen Naps . The most efficient way to heal , in the end , is to take " Regen Naps " Whenever possible . As a priest , your likely to have large amounts of spirit , so staying OO5SR is beneficial . Rather than healing every time the tank needs a heal , its more efficient to wait as long as possible , in order to stay OO5SR as long as possible , and heal in large waves , all at once . Followed by a renew and a Power Word : Shield , you can take rather long regen naps , which can sometimes lead to full mana before the tank needs to be healed again . If you were to heal every time the tank needed healing , even with the same gear and same tank , you would eventually run out of mana . Cheating the 5 second rule . The keyword in the paragraph above is that the spell must Cost Mana to put you into IS5SR regen . As a holy priest , you have a number of ways to cheat this . When you crit , you have a 50 % chance to gain Surge of Light , and a 45 % chance to gain Holy Concentration , both of which give you a free heal , which does not make you enter the 5 second rule . You also have Inner Focus to further extend your OO5SR regen , and inner focus can also be used to gain surge of light an holy concentration a second time , allowing you to take your " Regen naps " for large amounts of time , and keep healing .