Need to Know is an addon that keeps track of things for you. I've been a long time user of the addon but never really used it on my hunter. Perhaps for various reasons. One being it was my main and I was so used to it that I knew when things were ready and the other was we never really had a lot of things to look out for as a hunter. Keep that priority rolling, try not to lose even a fraction of a second between any shots and worry about that one cooldown (outside of trinkets) named rapid fire.
Now that the world of hunter goodness has changed we are full of cooldowns and we should be using them all the time. If you are a good hunter you have already taken A Murder of Crows and Dire Beast and will be taking Glaive Toss at 90 not to mention getting Stampede at 87, all that and there is the addition of readiness for non MM hunters.
So on top of what the average hunter needed to do, which was amazingly cooldown friendly, you will now have 5 (or 4 depending on if you played MM before and always had readiness) new cooldowns to keep track of. For most people this moves things from being easy to monitor with your memory muscle to something you might need assistance to keep track of. I know I will, at least while learning it.
For that I would like you to take a look at Need to Know or any addon like it that you might use. I know there are other addons that do the same thing but I like the slim look of NtK. I've always used NtK on my warlock and fire mage and even used it on my tanks to help monitor my defensive cooldowns when I was first learning.
What does need to know do?
It is a program that is very versatile in what it can do. It can keep track of the cooldown left on a spell, keep track of the time left on a DoT, notifies you of procs, and basically anything your little heart desires. You can change its location, appearance, even have it show little icons of the skill you are monitoring.
Each spec will have its own set too, so you can make it role specific and really any role can find a use for it. A healer can use it for cooldown tracking, a tank the same, just as a damage dealer would while keeping track of their DoTs and whatever else tickled their fancy.
Hunters however never really had much of a need for it. With only one slightly bigger cooldown in each spec outside of rapid fire, BA for survival, BW for BM and readiness for MM what else would you have really used it on? To track if your serpent sting was up on a target? Don't laugh, I did this for a while because I got into a habit of forgetting to use it when I first hit 85. Oops.
Now with all the cooldowns we have I think it about time that every hunter out there thinks about getting something like this. You might be able to do without it, we all will with enough practice, but it won't hurt to have it. It is a small program and will not cause any lag, never has for me.
Best part is, it was updated for 5.0.4 right away too. Something many addons were not.
So what should you do with it?
Here is how I am going to have it set up for me as survival. You could do hunters mark, to make sure it is on the target, sting, to make sure it is on the target and the cooldown left for black arrow and explosive shot if you really want but we are all used to that. So much so that not many even think of the cooldowns any more, we know when things are up without even looking. This is for the new stuff, save one, the one real cooldown we needed to watch before, rapid fire.
I use images of the spell because I like that, you do not have to.
1) Rapid Fire - Time remaining on cooldown.
2) Readiness - Time remaining on cooldown.
3) A Murder of Crows - Time remaining on cooldown.
4) Dire Beast - Time remaining on cooldown.
5) Stampede - Time remaining on cooldown.
6) Glaive Toss - Time remaining on cooldown.
So you can let need to know tell you when those things are ready or you can try to learn it all on your own. It is up to you. I know I used it on a few of my characters until I got comfortable with the timers and I will use it on my hunters now to get used to the timers. Once you got it down you can hide need to know again but it is a great tool to help you keep track of all those new cooldowns we have to deal with.
If you are like me and was spending more time looking at your spells yesterday to see when they came off cooldown, don't. Let this do it for you and you can get back to kicking some ass, just like us hunters are supposed to. Less time watching cooldowns means more time bringing the pain. Can you dig it?
So now hunters enter a new phase of life. It used to be a good hunter was the hunter that was best at responding to their priority and doing so even if forced to move. Our priority has always been a little brutal in how one mistake could effect our DPS and it still is. Now we added something new to the mix, cooldowns, lots of them.
Don't let those cooldowns interrupt that priority, it can mean a huge DPS loss. Integrate them. So the new version of the good hunter now is the one that is best at responding to their priority, uses their cooldowns for maximum up time and can do so even while moving.
Huntering just got harder, but it just got more rewarding too when doing it well. Need to know helps you make that transition into a cooldown class on top of everything we already were.
Other addons that do the same type of things that were suggested by posters:
Tell Me When