Healing Theory, Part 6: The Mana Economy

Previous posts in this series can be found here

Much of the focus on this series so far has been on Spirit and mana. Choices surrounding mana are some of the least obvious and most interesting character setup choices in WoW. They allow gear decisions to impact gameplay in a way that is somewhat unique. And, from our current perspective at the end of raiding in Mists, the story of how healing gameplay changed since launch is largely a story about mana. This is particularly interesting because I think, for reasons I discuss below, that the designers tried to avoid allowing healers to reach this point of having such ample mana at the end of Mists, after seeing it happen in Wrath and Catalysm.

This post continues the thoughts of earlier posts in the series, which focused on the difference between cooldown and non-cooldown heals and why that difference is important to an understanding of mana. Here I explore some of the theoretical foundation for that distinction and how it helps us make gear and play decisions.

The Balance Sheet: Mana Assets

One obstacle to understanding mana is that information about your total mana income and expenditures is obscure; in typical play, your only information is how full your bar is at a given moment. But since you spend many bars’ worth of mana in even a short encounter, this look is actually not too informative. For a better understanding of where your mana comes from and where it goes, we want to instead look at an accounting that considers an encounter as a whole.

Let’s work through a example on paper and see how it looks. What we’re looking for here isn’t a set of detailed output numbers, which would be better served by a full-blown spreadsheet like my TreeCalcs, but the overall picture and what it can teach us about the way we think about mana.

The first question is how much total mana I have to spend over the course of an encounter. That depends on many variables, but I’ll illustrate a typical hypothetical example for a 6-minute fight. I might have (values in thousands of mana):

Healer Pie

Since all of these returns are quite consistent, except for the small RNG fluctuations in the trinket and meta, I have a very good estimate of how much mana I might have to spend over the course of an encounter of this length. 1.9 million is just over 6 bars’ worth, which should indicate just how limited a view you get by thinking only about your one visible mana bar and how much of it has been spent. Aside: it might be interesting to think about an addon that shows this total at the start of the fight, and how much I’ve spent from it, as an alternative to the conventional mana display.

I left out for this purpose the Druid 2T16 set bonus and Clearcasting, which can only be applied to specific heals that aren’t often used otherwise (unlike the meta), and are more easily accounted for as free healing done rather than free mana. Similarly, the accounting might be a little more complex for certain refund mechanics like Rapture and Mana Tea, but as long as you treat them consistently as either added mana or as reduced costs, your results should be the same either way. To be specific, (jumping ahead for a moment), the curve of total healing done as a function of mana will ultimately look the same whether you think of some mechanics as taking mana and then giving it back, or as simply giving free casts. For purposes of a simple chart rather than a full class spreadsheet, I went with what I thought wouldn’t be misleading out of context.

In general, the picture would not change much for other classes. In fact, the entries other than Innervate and meta gem would not change at all. In place of Innervate, a Paladin would have 146k mana from 3 Divine Pleas, or a Priest 162k from 2 Shadowfiends at low haste (or 174k if one was aligned with Hymn). Shaman and Monk wouldn’t have any, as they only have mechanics that are easier to think of discounts rather than as mana income since they are based on number of spellcasts rather than time. And it turns out that the value of a meta proc is reasonably balanced across classes, loosely speaking, with many typical uses of a proc costing 20k or 30k mana: 2 Chain Heals, a Chain Heal and a Magma Totem, 2 Jabs with Muscle Memory return, a Holy Radiance, etc.

Variations

One key observation, to revisit a point I touched on in Part 2, is that Spirit is only 26% of this makeup (slightly more now that Innervate size depends on Spirit, which it didn’t before patch 5.4). In fact, the only changes that would be made to the accounting if I had 0 Spirit are that I’d lose the 487k mana from Spirit regen, and two Innervates would return 48k mana instead of 120k. The total would still be 1.33 million mana with 0 Spirit, 70% of what it was with 12,000 Spirit above.

One other number. Let’s say I’m back at ilvl 463 at the starts of Mists. The following things were different:

  • With around 5000 Spirit, I’d get only 203k mana from it over 6 minutes.
  • I had no legendary meta.
  • A standard-issue Int&mana trinket, Price of Progress, gave 30k mana in 6 minutes. (A ilvl 463 version of Horridon’s or Dysmorphic would have given closer to 42k mana at 12.5% haste. RPPM generally caused healer trinkets to get stronger).
  • Two Innervates still gave 120k mana, as it didn’t scale with Spirit then.
  • A Shaman with only 5000 Spirit would give me 36k mana with two Tides.
  • The new total is 1.17 million mana, 62% of what it was in the first example.
Mana Bar

Of the difference of 719k mana in this example, only 284k, 39%, is due to an increase in Spirit from 5000 to 12000. The difference would of course be even less if, like many people, you geared heavily towards Spirit early on and less so now. If you maintained similar gearing patterns, that increase from 5000 of a stat to 12000, a 140% increase, would correspond to a gain of 94 ilvls. The amount added from the meta (285k) is almost identical to the entire value of the added Spirit in this example (evaluated at 3 Rejuv casts proc, the meta is in fact worth 7000 Spirit).

So less than half of the mana difference between then and now is allocable to increased Spirit. In fact, you could wear 0 Spirit now (hypothetically–due to healer itemization you probably can’t wear 0 Spirit even if you want to) and have more mana than you did in the early part of the expansion, before the legendary meta.

The Balance Sheet: Mana Expenditures

What can I do with 1.9 million mana in 6 minutes? I’ll continue the example as a Druid, but it should not be too difficult to apply the reasoning to any class. My most important on-cooldown spell is Wild Growth. Let’s be generous and say I cast it every 8 seconds for the entire fight. In other words, I spend as much mana as possible on Wild Growth. 45 casts at 13740 per cast is 619k mana, just under 1/3 of my supply. Similarly a Swiftmend every 16 seconds would add another 115k spent. Lifebloom is very small; even if you manually refreshed it every 14 seconds (as opposed to using Clearcast Regrowth or 2T16 Healing Touch), it would be 91k mana. In reality it will be much less.

The most a Druid can possibly spend on the core rotational heals in 6 minutes is around 800k mana. The remainder is the discretionary budget for no-cooldown heals. That means that I have over a million mana to spend on Rejuvs (including the free ones from the meta), even with the occasional Bloom or other odd spell. 1.1 million mana is 126 Rejuvs, or about one every 3 seconds over the course of the fight.*

Thinking back to the comparison above about mana resources available at the beginning and end of the expansion, let’s see how that chart would look if it was colored to reflect the mana expenditures (instead of mana income) in this simplified model:

Mana Bar 2

You probably don’t play precisely like this. But if you imagine an encounter with relatively consistent healing needs, such that you rarely got for long stretches without casting Wild Growth, this is quite a serviceable picture of how should strive to play. In particular, of how your spell use should be affected by variations in your mana supply. The point illustrated by this graph is one that’s been a consistent theme of this series: extra mana affects how much you use your class’s best heal that has no cooldown (in this example, Rejuvenation). As Part 3 discussed in depth, when healing in a limited-mana environment, you want to solve problems with your efficient cooldown-bearing, rotational heals as much as possible. In other words, by trying to mimic the left bar in the above graph. The more you lean on the spammable (and lower-HPM) heal before you have the resources to support it, the more you cut into your ability to use your best heals as much as possible throughout the fight.

For your interest, here are some references on mana usage from other major rotational spells. To fit with this post, I’ll continue to express these as theoretical max mana (in thousands) spent on a spell in 6 minutes, rather than mean MP5:

*Druid-specific aside: so you simply can’t spam Rejuv nonstop for the entirety of an encounter. If you feel like you do, it’s because you’ve stopped noticing the intuitive pauses most of the time, that let you spam it fully during intense healing phases. It’s a class that requires casting nothing some percentage of the time (although that percentage is small at the gear levels we’re discussing here). Less experienced Druids often haven’t picked this up, and spam Rejuv too readily, resulting in the feeling that they have mana problems or need more Spirit.

The Mana Curve

The above description, that I called a simplified model of casting, differs from reality in two important ways. First, if the upkeep of your rotational heals is too large compared to your total available mana, it can be impractical or impossible to heal using those alone. Second, variation in healing needs during an encounter mean you sometimes need to stack filler heals onto cooldown heals in high-demand moments, regardless of ideal mana planning (notice how these two issues are related).

I’m going to draw the same picture I drew in the previous section, but in a different way. This one is purely conceptual–not to any scale.

Healer Diagram

There’s a lot going on here. If you had 0 net mana to spend, the only healing you could do is with your free heals (e.g EfflorescenceRecalled Healing Stream Totem, Chi Wave). The first points of mana you spend allow you to cast efficient, cooldown-based heals that all classes have. As you fill up on your capacity to cast those as many times as possible per encounter, you spend each marginal point of Spirit on less efficient heals, until you get to the one with no cooldown, which each added point of Spirit is spent on. This is the story I’ve been telling so far, and is reflected in the blue line.

The red line shows what’s more likely to happen in practice, and reflects the two points I just mentioned. Transitions from one phase to another are smoother, since you’re starting to mix in the less efficient heal as needed before fully capping out on use of the previous heal. In particular, at the cusp between the “cooldown” and the “no-cooldown” phase (around where the “curved in practice” arrow is pointing), your filler heals have to be mixed in to some extent in any healing scenario, and they will cut into core heal usage until you have more of a cushion of mana. This results in Spirit retaining some higher value even past the cusp, as you establish enough of a reserve to use the rotational heals to their full extent in practice. While Druids tended not to be too much affect by this early in Mists, Shaman were more so (see this comment from Vixsin and my reply on an earlier entry, anticipating this post). For reference, before the Healing Rain cost reduction mid-Mists, casting a Healing Rain (25860 mana) every 11.5 seconds for 6 minutes took 810k mana, and the Shaman’s mana supply would have been closer to 1 million rather than 1.1 million since they do not have Innervate.

The other important feature of the red line is that its growth falls off when you have a large amount of mana. The problem with continually adding filler heals by increasing in mana is that they only allow you to add healing in one way: more and more uniformly spread over time. At some point, you are already casting full-time during the demanding parts of an encounter, and more mana simply lets you add in casts at other times, which is not especially useful. This is what’s generally responsible for the class-wide turn away from Spirit among healers. As we got to the end of Mists (bearing in mind the large role the meta gem played here), we had the mana to cast at all the times we wanted to. There’s little reason for anyone to go out of the way for more.

In between these two extremes is a roughly linear range where more Spirit allows more useful casts of filler heals. This is primarily where my previous discussions were aimed, where Spirit gear is the most interesting, and where I believe healers are intended to be. The slope of the line in this region corresponds to the efficiency of your best no-cooldown heal, as described in Part 3.

Inflation in Mists

The story of mana in Mists is once again one of healers having more of it than is ideal by the end of an expansion. It’s not as drastic as it was in Wrath or Cataclysm, due to measures the designers took to prevent this. Base mana no longer increases with Intellect. Spirit regen no longer scales with the square root of Intellect (which used to cause it to scale with the 3/2 power of your stats). There is no longer powerful regen like Replenishment based on your max mana (and therefore scaled with Intellect). And the effects of these changes are clearly visible–our total available mana has increased by less than a factor of 2 from the beginning of the expansion to the end, whereas, for example, DPS has increased by far more than that. For raiders with the highest available gear, ilvl 580, total character stats are 297% of where there were at ilvl 463. So healer mana has been kept much more under control than in the past. If not for the singlehanded effect of the legendary meta, this discussion would probably be quite different.

When I first saw the legendary meta, I didn’t think straight away that it was overpowered. Because from a certain perspective, it’s not. The value of the DPS metas to DPS classes is similarly huge. The goal of these legendary rewards was to feel like they brought a transformative bump in character power. The problem with healers was pouring that sudden increase in character strength all into the mana balance. It counteracts all the work described above to make sure that the difference in mana between the beginning of the expansion and the end was not overwhelming. And even with the meta, the situation is not disastrous–mana is dancing around the boundary of being a nonfactor, but has not fallen completely into it. It’s just far enough that you generally don’t want to gear for more.

For some stats, it’s totally fine if they increase by a completely arbitrary amount between the beginning of the expansion and the end. Most importantly, attack power and spell power. These overall damage/healing multipliers could increase by 1000% if the designers wanted them to and it wouldn’t cause any mechanical problems. Haste is a more complicated since it affects the pace of gameplay, you can’t let it get out of control. Healer mana, more than any of these others, wants to stay in a tight range where you don’t have too much and don’t have too little. The importance, and generally low cost, of rotational heals provides an important foundation–it ensures that there is a well-established playstyle for each class even in low-mana setups. Beyond this, Spirit needs to be tuned so people can use filler heals in a small (but not too small) portion of free time at the beginning of the expansion and a large (but not too large) portion at the end.

Conclusion

I started discussing healing in Mists with arguments that people overvalued Spirit as the expansion started out. This was based primarily on the fact that you had a solid core rotation of cooldown-based spells even at minimum Spirit, and throughput stats leveraged those existing spells for added healing that you really needed as you were getting stated. Midway through Mists were the middle posts in this series, looking at the value of Spirit in the ideal range (for the purpose of interesting choices), where you could choose between more throughput on existing casts, or more casts of a filler heal. And now, while those discussions are little academic to most people due to the current state of healer gameplay, there is still a good opportunity to look at the big picture of how mana works, in anticipation of the next iteration of the game. As you can see, the framework in this post is consistent with all of the discussion so far.

This discussion, I think, will continue in full force in Warlords. While they’ve announced that Spirit will be on fewer pieces (to facilitate hybrid gearing), that won’t make the question go away. It will only eliminate the option of full Spirit stacking, and perhaps make it a little easier to limit the variation in mana between the beginning and end of the expansion. I don’t expect we will see something like the healer meta gem again. I look forward to seeing how the theory applies as soon as we have detailed info on the classes in Warlords.