Ultimately, there are two incredibly important haste breakpoints: 916 and 2005. These numbers assume that you are raiding with, at minimum, a 5% haste buff from another member of your raid - something that is almost guaranteed given the prevalence of that particular buff. [if you'd like a more complete breakdown, this post via The Inconspicuous Bear gives several more breakpoints based off of the presence and lack of both the 5% buff and/or Dark Intent]. Also remember that this total includes any food buffs you may be choosing to use, so if you are just shy of a breakpoint but will be brought over by food, absolutely take advantage of that.
The next question that I've seen quite often refers to the exact reason why haste is so important. First and foremost, and perhaps most obviously, it effects your overall cast time and GCD. More importantly, at certain levels haste gives you extra ticks on your HoT spells - and this is awesome.
916 - When you have hit this breakpoint, you have gained the an extra tick on Lifebloom, Wild Growth, Efflorescence, and Rejuvenation. The gain from this extra Rejuvenation tick effectively gives it a 20% boost in power.
2005 - This brings you to yet another Wild Growth (and Efflorescence) tick, as well as the extra ticks from HoTs gained at earlier breakpoints.
[Note: This table does not break down intermittent haste points, only total ticks at both of the points I have mentioned.]
| Spell | Original Tick | 916 | 2005 |
|---|---|---|---|
| Lifebloom | 10 | 11 | 12 [13 with DI] |
| Wild Growth / Efflorescence | 7 | 8 | 9 |
| Rejuvenation | 4 | 5 | 5 |
| Tranquility | 4 | 4 | 5 |
| Regrowth | 3 | 3 | 4 |
Now, while 916 doesn't seem like a hard number to get to, 2005 absolutely seems a bit daunting. The rule I used when making efforts to get to 2005 is as follows: pick up all of the Haste enchants that you can. Aim for gear that either has a high amount of haste, or that can be reforged to give you a boost to haste. If switching out a piece of gear gives you a negligible gain to other stats but causes you to lose a great deal of haste, it may not be worth it in the long run. This is particularly true if switching out a piece of gear takes you below a breakpoint that you have previously reached - ultimately something like an extra 20 intellect isn't going to be worth losing 25% overall of your Wild Growth casts.
Do not waste gem slots on pure haste gems - intellect in this case is much more important. Make use of Reckless gems (20 haste / 20 intellect) for yellow gem slots when necessary. Ultimately, intellect and spirit are more important than haste, but it is easy to benefit and balance these stats while focusing on haste if you are able to prioritize effectively.
Coming soon will be a more detailed post about gems, enchants, and early gear choices.