Enduring Renewal is a talent that’s had a bit of a hard time this expansion. Prior to 7.1.5, it suffered from being on the same talent tier as Trail of Light, which back then allowed Blessing of T’uure to have two chances to proc when casting Flash Heal. This meant that ToL was such a strong talent that ER couldn’t even come close to competing. When 7.1.5 was released, the extra BoT proc chance was effectively removed from ToL, but changes were made to PoH which pushed us towards filling with PoH when possible. This meant that Enlightenment was generally a better choice except on fights where you needed strong single target throughput, where it was a good choice to switch to ToL to make spot healing checks. In general, prior to 7.2.5, Enduring Renewal pretty much only saw play as part of the ER/Binding Heal “meme build”.

However, due to the recent changes to Binding Heal, BH has been seeing more play, and now that BH is good it means that on some fights it may be a good idea to consider complementing it with ER. But mechanically, ER behaves a bit strangely, so in this article I’m going to go over exactly how it works.

## Disclaimer

**This information doesn’t really matter from a game play standpoint. It has very little effect on balance/the ideal stat distribution, and means very little for the average player. Do not read any of this and make decisions thinking it has a tangible effect on your game play, talent choices or decision making. It doesn’t.**

## Renew

First, let’s take a look at how the spell Renew actually works. It’s useful to think of it as a spell that does two things- first, it applies a direct heal to the target, which works like any other direct heal in the game. Then, it applies a periodic heal effect. This is why only the initial heal procs mastery. It also impacts the number of heal events with a given haste level as only the periodic effect scales with haste. For example, Renew has the initial heal and 5 ticks with no haste. With 20% haste, Renew has the initial heal and 5*1.20 = 6 full ticks, for a total of 7 events. If the initial heal was counted as a tick, only 16.67% haste would be required for 7 events.

### Pandemic

Renew refreshes also proc this initial tick as normal, but they have an interesting impact on the periodic effect because of a mechanic nicknamed “Pandemic”. This means that if you refresh Renew with 30% or more of Renew’s original duration remaining, 30% of the original duration will “carry over” to the refresh. If you refresh with less than 30% of the original duration remaining, the time left on the aura carries over. For example, if you have 10 seconds left on Renew when you refresh, the duration of the new buff will be 19.5 seconds. If you refresh with 4.5 seconds left, you’ll still have 19.5 seconds. But if you refresh with 2 seconds left, the resulting duration will only be 17 seconds. The Pandemic mechanic allows players to keep 100% uptime on a DoT or HoT effect without wasting any duration. It also means that refreshes can cause the spell to go significantly above the duration on the tooltip- Renew can go up to 19.5 seconds baseline and 27.3 seconds with Pants.

### Partials

The other important mechanic that periodic effects have are partial ticks. Partial ticks were a mechanic introduced into the game to remove haste breakpoints, which used to exist because there was a set amount of haste that would give you an extra tick on a periodic effect. If you were at that point, you got an extra tick, if you were below that point, you got nothing. Now, partial ticks fix this by being a smaller tick added onto the end of a periodic effect. How far you are to your next tick determines the size of the partial- If you’re 50% there, your partial will be 50% of a full tick. This ends up meaning that the healing done by a periodic effect scales totally linearly with haste. If you have 20% haste, Renew will do 1.2 times the healing than it would if you had 0% haste.

Overall, this means that the amount of healing coming from Renew is directly proportional to the formula (1+baseTicks*haste), where baseTicks is normally 5 and 7 with Pants.

## Enduring Renewal

So what’s special about Enduring Renewal? In a sentence, it doesn’t cause a refresh event. Instead, it sets the remaining duration of Renew to be exactly enough for a set number of ticks which depends on your haste. For example, if you have zero haste, no matter when you cast a single target heal, Renew will always tick exactly 6 times (8 with pants). This has a few interesting implications.

### Mastery

First of all, the initial direct heal mentioned above doesn’t exist. This doesn’t really matter that much- it pretty much means that ER refreshes can’t proc mastery. **This doesn’t really have an impact on stat weights- the difference is negligible.**

### Partials

Second of all, the refreshes don’t have any partials. I’m actually not sure if there’s a technical reason for this- I haven’t observed a reason that they can’t, so it’s possible this is just a bug/oversight. This means that every time you let an ER-refreshed renew expire, you might lose a little bit of healing- but never more than a full tick of healing. That means while technically there’s points at which you get 1 more total tick out, given how rarely ticks actually reach that point with ER, it’s not worth worrying about. It’s also worth noting here that if your haste changes partway through the Renew buff, you can actually still get a partial, as the logic can be abstracted to (at the point of the ER “refresh”):

- Figure out the interval between Renew ticks
- Figure out how many ticks to extend by
- Set the duration to [ticks] * [interval] – [time since last tick]

There’s nothing actually counting the number of ticks after the ER “refresh”, and it behaves exactly like a regular periodic effect from that point forward, which allows for partials if the tickrate changes midway through.

### Haste Scaling

Third of all, haste scaling with ER is kind of weird. With a Renew that hasn’t been refreshed with ER, it takes 20% haste to get an extra tick- before that it’s just a partial. However, the numbers at which you get an extra tick with ER are different, and they aren’t the same as a 6 tick periodic effect either. 10% haste will give you 1 extra tick, 30% haste will give you 2, 50% will give you 3, and so on and so forth. With Pants, we figured from testing that it changes not at, but sometime right after 7%. These values essentially tell us that ER tries to keep the number of heal events the same as a hardcasted Renew, still following the formula (1+baseTicks*haste). Because there are no partials, the formula rounds to the nearest whole number. If the formula results in 6.49 you get 6 ticks, but a result of 6.51 gives you 7.

**This doesn’t mean you should gear to hit these breakpoints- they have little to no effect on your overall healing and you can pretty much pretend they don’t exist.** If you’re unconvinced of this, take a look at the table below:

*Information about the avg value of hitting the above breakpoints. Healing is presented as a percentage of overall healing done.*

Knowing how ER works, it was relatively trivial to parse through a few hundred logs and estimate how much healing was done by hitting the last haste breakpoint. The results were pretty underwhelming- given how far the breakpoints are away from a reasonable stat distribution, it’s fairly obvious **it isn’t worth it to gear for these**.

### Pandemic

Last of all, and probably most interesting, ER refreshes interacts with the pandemic mechanic very strangely. First of all, the actual ER “refreshes” don’t actually have a pandemic mechanic- if you cast a heal on yourself, it doesn’t matter if you’re in the last millisecond of the duration or the first. The number of ticks always remain the same. That means that the number of heal events that you get out of ER is smaller than a manual refresh. Even though if you look at the timer ingame Renew‘s duration can go up to as far as 18 seconds after an ER refresh, that’s because that ER doesn’t start with a heal event like a normal refresh would, so there’s a delay between the “refresh” and the first heal event. The other interesting interaction that ER has with the pandemic timer is that as ER always sets the duration to allow for a constant number of ticks- which means that if Renew is above the non-pandemic duration, Renew’s duration can actually *decrease*. This is very visible especially with Pants– casting any single target heal right after manually refreshing Renew makes it clear that the duration drops.

## Results

**This information doesn’t really matter from a gameplay standpoint. It has very little effect on balance/the ideal stat distribution, and means very little for the average player.** For theorycrafters, specifically anyone looking to create any sort of log parser or analysis tool to try to divine the benefit of Enduring Renewal/Pants, this information is important. For everyone else, it’s just an interesting insight into this particular mechanic.