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 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.
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:
- Prayer of Mending
- Greater Heal
- Prayer of Healing
- Circle of Healing
(Note: Prayer of Healing and Circle of healing; to be more efficient then greater heal; require more then 3 targets to need 100% of the healing spell without overhealing. In addition, the efficiency of Greater Heal and Flash Heal is greatly improved due to the Serendipity talent if you overheal, but by less then 25%)
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.
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.