I need to know why it's a dumb idea to go Leatherworking on my warrior.

[Fetzie]

The bit starting

Complete Magic Resistance Mechanics for Catalysm
I stumbled upon something else when checking avoidance dr caps, and I took a detour of figuring out the resistance formula for all levels up to level 88.

[justinlee]

i think blacksmithing and Jewelcrafting still the best professions for a Warrior tank, 70resistance seems better in some fights , just like Nefarian， Maloriak andMagmaw.
But in other bosses , it seems worse than blacksmithing.
Add 2 sockets, and have extra mastery on 3 gems make u have many different choices.

[jere]

For reference, each partial resistance tier (0%,10%,20%,30%, etc.) is guaranteed when your average resistance reaches 10 more than that tier. That can be found by working out P(x) = 0.5-2.5*|X-A| for each partial resistance tier and seeing where it equals 0.

So for example, to see what average resistance you need to guarantee 10% partial resists, you look at the previous partial resist tier, and solve P(x) = 0 for it:

P(0%) = 0 = 50% - 2.5*|0%-A|
50%/2.5 = |0%-A|
20% = |0% - A| (HINT: this step is true for all partial resist tiers)
A = 20%

So when you have 20% average resist, you have a 0% chance of having a 0% resist and are guaranteed at least a 10% chance to resist.

To see what the minimum average resist is for a guaranteed 20% resist, look for P(10%) = 0


20% = |10% - A|
A = 30%

So when you have 30% average resist, you have a 0% chance of having a 10% resist and are guaranteed at least a 20% chance to resist.

Putting this into a table:

Guaranteed Min Resist     Average Resist Needed     Resistance Value (vs LvL 88)
10%                       20%                        181
20%                       30%                        311
30%                       40%                        483
40%                       50%                        724
50%                       60%                       1086
60%                       70%                       1690

You can't get any higher than 60% guaranteed since your average can't exceed 75%


EDIT: Here is a table showing the values of P(x) for each resistance tier for 5% increments of average resist:

                          Partial Resist Tier Probability P(X)
AVG  |  0     0.1   0.2   0.3   0.4   0.5   0.6   0.7   0.8   0.9   1.0
-----------------------------------------------------------------------
0.10    0.25  0.5   0.25  0     0     0     0     0     0     0     0
0.15    0.125 0.375 0.375 0.125 0     0     0     0     0     0     0
0.20    0     0.25  0.5   0.25  0     0     0     0     0     0     0
0.25    0     0.125 0.375 0.375 0.125 0     0     0     0     0     0
0.30    0     0     0.25  0.5   0.25  0     0     0     0     0     0
0.35    0     0     0.125 0.375 0.375 0.125 0     0     0     0     0
0.40    0     0     0     0.25  0.5   0.25  0     0     0     0     0
0.45    0     0     0     0.125 0.375 0.375 0.125 0     0     0     0
0.50    0     0     0     0     0.25  0.5   0.25  0     0     0     0
0.55    0     0     0     0     0.125 0.375 0.375 0.125 0     0     0
0.60    0     0     0     0     0     0.25  0.5   0.25  0     0     0
0.65    0     0     0     0     0     0.125 0.375 0.375 0.125 0     0
0.70    0     0     0     0     0     0     0.25  0.5   0.25  0     0
0.75    0     0     0     0     0     0     0.125 0.375 0.375 0.125 0

[Maxadon]

Thank you Jere, really appreciate all that information. I feel like I've done enough research to know that this will actually help my spot mitigation as a tank more so than the stamina or mastery gained from this or any other profession. The fact that Blacksmithing gains value over time (when epic gems are released) whereas Jewelcrafting severly loses value when this happens has led me to choose blacksmithing and leatherworking as my primary professions at the current time.

I said I would post logs of our next heroic nef pulls, but we didn't have our raid group available tonight so we just did it on normal. Here are the logs.

http://www.worldoflogs.com/reports/y...cp3iya6ms/log/

[edeesis]

When Epic gems were released in Wrath, Blizz buffed the Dragon's Eyes to give more of each stat, to compensate. I'm assuming they'll do this again.

[swelt]

I think there's a severe lack of perspective in this discussion.
- Profession perks are hardly game breaking. You can effect a much bigger shift in total character statistics by changing 1 trinket than you can by changing your professions. As long as you haven't picked a *bad* one (herbalism, skinning, tailoring) then you are getting some useful benefit.
- People are talking about T11 bosses as if they are in any way important. Time has moved on. Start thinking about T12 bosses. I hear there might be some fire, but has anyone looked to see if there are any life threatening (heroic crackle style) magic bursts? With the new shield block, would we even have to worry about gearing for them rather than just managing them with cooldowns anyway?

Only 2 professions have the option to give magic resistance: alchemy and leatherworking. Both professions have the downside that they have limits on their flexibility (lw can just have stam/str/resist, alchemy can flask for stam but not elixir for it so armor/mastery or resist/mastery are the only options that will give you the full profession benefit - the stam scroll won't get mixology bonus). Those limitations aren't much different to most other professions, and it's why the JC+BS combo is often touted as 'best', as it's in many ways the most flexible.

[Airowird]

Thanks for the numbers jere.
So in other words:
For overall damage reduction, resistance is pretty ok (no DR!), depending on how much damage is magical.
For burst reduction, get >311 or the worst case scenario stays the same.

Imho, 311 ain't worth changing to LW for, but if you already are, the question you should ask yourself should rather be:
Is it worth switching to JWC/BS for the flexibility in stats?
Personally, I'ld say not, but it's your time & gold spent rerolling professions, especially when (as swelt pointed out) you can use that time to farm mats for a more significant gear upgrade instead.