A little introduction
Clarity is a must-have in ARAM. It provides a large amount for mana and the more people are around you, the more it is effective.
If your team plays correctly, then it means that they use their abilities as often as when they are able to hit your opponents. And if they do so, then their mana gauges will inevitably end up getting depleted, even if they have for example a Tear of the Goddess.
If your teammates always have a lot of mana, it doesn't mean that they are good at saving it up. It often means that they just let occasions to hurt the opponents pass because they know they can run out of mana very quickly.
You should always have at least on Clarity in your team if you play in ARAM, unless if you have too many energy users in your team such as Lee Sin or Katarina.
I will provide some calculations to you in order to explain clearly how useful Clarity is.
Calculations for level 6
If you effectively use Clarity on someone, you can restore at least 150 mana points. Let's see what you can do with these 150 points.
- Nidalee can throw 2 Javelin Toss and inflicts about 420 damage if they hit.
- Blitzcrank, who is a champion who often runs out of mana, can use his deadly combo Rocket Grab + Power Fist.
- Lux can use a combo Light Binding + Final Spark, which can deal 400 damage.
- Jayce can use his combo Acceleration Gate + Shock Blast and can deal 300 damage.
- Ashe can harass the opponents with Volley 3 times, dealing 350 damage and slowing them down.
No matter how you see it, this is way better than a 235 HP Barrier, right?
Note that all the indicated damages are "pessimistic". In other words, they represent vaguely the damage you would deal if you didn't use your abilities with their best potential (if you only hit one opponent with Lux's ulti, etc).
For example, if you had some mana and AP items on Nidalee and that your two Javelin Toss hit an AD carry far away, you could deal more than 400 damage.
350 + (80 AP x 1,625) = 350 + 130 = 480 damage
480 - 35% because of the opponent's armor = 312
312 x 2 since you can throw your attack twice = 624
624 + 312 = 936 since Nidalee has in fact a little more than 200 mana restored at lvl 6.
So, you could potentially deal 936 damage, which is very pale in comparison than a mere 235 HP Barrier.
Of course, these were the calculations for what would happen if you used Clarity well on a single champion. But since you can restore up to 5 champions' mana gauges, Clarity can be even more tremendous!
Moreover, in the calculations, I wrote what the champions could do if they got 150 mana points restored, but in fact most of them receive more than 150 points, especially if they have mana items. In addition, Clarity's CD is 30 secs lower than Barrier's CD.
The best situation that one could dream of
It's just an exemple to demonstrate Clarity's potential. Such a situation will never happen.
In your team, you have Nidalee, Blitzcrank, Lux, Jayce and Ashe. Everyone is level 6 and, plays perfectly and hits many enemies with every attack they throw. You are completely dominating the opponents. These opponents can't do anything against your team because you outplay them. Unable to counter-attack, they keep getting poked because you always use your abilities without stopping.
But at some point, the you and your teammates only have about 20-50 mana points because you used your attacks too many times. Then someone suddenly uses Clarity!
With their restored mana...
- Nidalee deals 1000 damage.
- Blitzcrank 350 damage.
- Lux deals 700 damage.
- Jayce deals 500 damage.
- Ashe deals 600 damage.
For a total of 3150 damage. Plus the CC.
While this time, you laugh at one of your opponents when you see him uses his tiny 235 HP Barrier...
To summarize... (skip to this part if you don't want to read everything)
If you have one Clarity in your team, this Clarity will most of the time prove itself to be 2 to 3 times more useful than if you took Barrier.
So, don't hesitate to take Clarity in ARAM if no one else takes it and don't listen to people who say that it is an useless summoner spell.
If you are Ashe, don't hesitate to poke the opponents all the time with Volley... You have a long range, so there is no point in not hurting the opponents when you are able to do it while staying unharmed.