Inner Fire / Inner Will

[scarryterry25]

The math you need to solve IW vs IF is not actually called Math but called Logic...IW generally means you can cast 1 more spell for each 10 you cast...

Not sure how you got 1 for 10. PoM cast 4 times with IF = 13340 mana vs PoM cast 5 times with IW = 13895 (that's about 1 more/4). Maybe you did some mathmatical calculations with a logical ratio of instant cast to non-instant cast spells, or was it purely subjective?
PoM: 3335/2779
Renew: 3150/2625
CoH: 3890/3242
Say you don't cast any other instants other than the 3 above with PoM and CoH on cooldown and Renew kept up only on the tank. That would give you 821 M/5. If you have 7K int and 2.8K spirit your combat regen would be 4164.
IF +10% SP raid buff will give 585 SP.
HPS is proportional to heal size and inversely proportional to cast time.
So in order to come up with an answer to the posters question we need a stat weight of SP to haste. EJ has a SP 37% stronger to haste while Mr.Robot has the stats equal. Lets use EJ's. So now with this stat weight we know it takes about 800 haste to replace the same theoretical HPS IF gives. So what happens to our regen if we drop our spirit by 800 to get the needed haste? Your regen will drop to 3268, taking IW's mana savings into account that's a loss of 75 M/5 so IF would be stronger. Use Mr.Robots stat weights or cast a few more instants and you would achieve higher HPS with IW.
I believe this example is skewed slightly in favor of IF. I would expect more instants used in most fights and I think Mr.Robots stat weight is more accurate.

[Felade]

math-wise, the other thing to consider is that Inner Fire actually increases efficiency as well. Efficiency is measured in HPM - that is, how much healing you get for each mana point spent. Spellpower gives you more healing, while mana costs stay the same. It is similar to the argument around Power Torrent/Heartsong - Heartsong and Inner Will both give you regen, but Power Torrent and Inner Fire give you comparable regen (or effective regen through increased HPM) and significant throughput.

Add into that the fact that Inner Fire affects *all* your spells while Inner Will affects only instant casts and you beging wondering why people ever used Inner Will at all, other than for the speed boost, and moments of high instant-cast use.

Inner fire (increased HPM, increased throughput, affects all spells) >>> Inner Will (only affects a few spells, only increases HPM, not throughput)

The only time I've found, mathematically, that Inner Will is an HPM increase over Inner Fire is when you are spamming PW:Shield as Disc.

[Afflictid]

Not sure how you got 1 for 10. PoM cast 4 times with IF = 13340 mana vs PoM cast 5 times with IW = 13895 (that's about 1 more/4). Maybe you did some mathmatical calculations with a logical ratio of instant cast to non-instant cast spells, or was it purely subjective?
PoM: 3335/2779
Renew: 3150/2625
CoH: 3890/3242
Say you don't cast any other instants other than the 3 above with PoM and CoH on cooldown and Renew kept up only on the tank. That would give you 821 M/5. If you have 7K int and 2.8K spirit your combat regen would be 4164.
IF +10% SP raid buff will give 585 SP.
HPS is proportional to heal size and inversely proportional to cast time.
So in order to come up with an answer to the posters question we need a stat weight of SP to haste. EJ has a SP 37% stronger to haste while Mr.Robot has the stats equal. Lets use EJ's. So now with this stat weight we know it takes about 800 haste to replace the same theoretical HPS IF gives. So what happens to our regen if we drop our spirit by 800 to get the needed haste? Your regen will drop to 3268, taking IW's mana savings into account that's a loss of 75 M/5 so IF would be stronger. Use Mr.Robots stat weights or cast a few more instants and you would achieve higher HPS with IW.
I believe this example is skewed slightly in favor of IF. I would expect more instants used in most fights and I think Mr.Robots stat weight is more accurate.

You aren't factoring in that you will have to do less healing with IF because of stronger heals. You shouldn't be using PoM and CoH on cooldown. At least a couple people should be damaged before using CoH, and PoM needs to bounce 2-3 times to be efficient.

The way I look at it is... if my raid is in the situation where I need to be pumping out heals, would I rather heal for more on everything, or would I rather save 15% mana on spells that are already considered efficient?

[scarryterry25]

@Felade: **HPS is proportional to heal size and inversely proportional to cast time.**
So if you can have a buff like IF that increases your healing from 10K/S to 15K/S that is a 50% increase in HPS and HPM.
Now if you have a buff like IW that because of its mana cost reduction on certain spells allows you to drop enough spirit for haste that all of your spells will be cast in 2/3 the time (50% faster) it otherwise would have taken (10K in 2/3rds of a Second) is still 15K/S and the same increase in HPS and HPM.
@ Afflictid: Yes you should be smarter with PoM and CoH, I was just giving an example, but while you may not need to use those spells on cooldown you also will be using other instant cast spells. And the way I look at it is...
If I have the choice of increasing my HPS/HPM by X% because I made my heals larger or faster I would pick faster heals.

Now I am not trying to advocate that IW is stronger than IF or vice versa. I was attempting to point out a concept that appeared was overlooked. That concept was that IW can also be used to increase HPS/HPM. If it will be enough to make it a better choice than IF depends.

[eErike]

Easy and short answer:

People who do not oom use Fire
People struggeling with mana use Will

Tada!

[Eis]

Inner Will does have its place, especially on Heroic Rag. You do shield quite frequently, and its a noticeable difference for me as disc. I do stay in will for the duration of the fight. Overall though, for normal modes and 6/7HM you should use Inner Fire. Just my 2c from personal experience. As for Holy, I would say Inner Fire no contest.

As holy on H Rag, Inner Will is amazing. I renew so much. But, that's seriously the only fight I've used it on since... um... I was in blues? (Okay, well, I used it on H Magmaw for renewing too. But that.. almost counts.)

Basically, for holy at least, if you're finding that it's a fight with loads of raid damage while spread out and/or running and you're using renew a lot, IW can be useful. Otherwise, IF.

[Afflictid]

@Felade: **HPS is proportional to heal size and inversely proportional to cast time.**
So if you can have a buff like IF that increases your healing from 10K/S to 15K/S that is a 50% increase in HPS and HPM.
Now if you have a buff like IW that because of its mana cost reduction on certain spells allows you to drop enough spirit for haste that all of your spells will be cast in 2/3 the time (50% faster) it otherwise would have taken (10K in 2/3rds of a Second) is still 15K/S and the same increase in HPS and HPM.
@ Afflictid: Yes you should be smarter with PoM and CoH, I was just giving an example, but while you may not need to use those spells on cooldown you also will be using other instant cast spells. And the way I look at it is...
If I have the choice of increasing my HPS/HPM by X% because I made my heals larger or faster I would pick faster heals.

Now I am not trying to advocate that IW is stronger than IF or vice versa. I was attempting to point out a concept that appeared was overlooked. That concept was that IW can also be used to increase HPS/HPM. If it will be enough to make it a better choice than IF depends.

What other instant cast spells?