Considering bot lane, it is customary for the ADC to build ONLY armor or armor pen while the support builds his gold income and sightstone. The idea behind this is for the ADC to be able to dish out as much damage as possible while depending on his support to keep him alive. I get this - it sounds reasonable.
What if you beleive you can last-hit just fine, you want to be able to trade well against the enemy, perhaps even win a 2v2 or 1v1 engage? Obviously as ADC you also would like to stay alive during a full engage, making hp or armor/resist a wish. What it comes down to is prioritizing, i get that. I also get that everyone seem to prioritize building only damage. I just don't get WHY. Say you go back as adc with 875 gold, so does the other adc. One of them buys a pickaxe the other one buys a chainmail and health pots. Once back in the lane, the fighting starts to break out. Let's examine the following scenarios:
- Only the two adcs are present (both supports still at shop or for some reason just recalled). 1v1
- All four bot laners are back in lane. 2v2
- Disengage and continue to farm and harass
The defense adc can pop a potion just before the engage (chain mail being cheaper than pickaxe), effectly increasing hp as well. Let's also assume both teams target the enemy adc. The pickaxe adc will dish out more damage (+25) per hit, only to get it reduced by the armor (+40).
The way i understand armor is, that each 1 point in armor is increasing (effectively) hp by 1%. Making the armor a +40% hp. I'm aware this only works for attack damage, meaning any magic or true damage will go though as normal.
I'm aware the calculations are getting pretty hard now, so i'm gonna try and simplify it by assuming it's only a 1v1 adc/adc match. Also i'm assuming all damage from both sides is going to be pure physical since after all we are comparing a physical boost (+25 attack damage) to a physical defense (+40 armor).
Let's also assume both adcs are caitlyn (honestly it's easier and also my lol assistant listed her as free this week, making it easy to one-click and read stats). Let's assume they are both level 5.
(Effective) hp for damage adc: (390hp + (4 lvl * 80hp)) * (1 + (17armor + (4lvl * 3.5armor)) / 100) = 710hp * 1.31 = 930hp (Effective) hp for armor adc: (390hp + (4 lvl * 80hp)) * (1 + (17armor + (4lvl * 3.5armor) + 40 armor) / 100) = 710hp * 1.71 = 1214hp
Giving the armor adc an extra (excluding the healing pots) 1214hp-930hp = 284hp (it's equivalent to 710hp*0.4armor - just wanted to make it clear that i was factoring it all in)
Let's finish it up. 284hp/25 damage = 11,36
Without calculating the healing pots, the damage adc will win the engange if it lasts beyond 11 (atleast 12) auto attacks. That is a lot of auto attacks. Consider a normal fight - it should last less than that if you factor in the skills again (QWER) and also if you calculate the supports. Speaking of which. If supports are pure AD based, the favor obviously still swings towards the defense adc. If the supports are pure AP (kind of unrealistic since auto attacks should still be ad) then the formular still holds. The factor damage dealt/received by the two adcs would still favor the armor untill the 12 adc auto attack. Which will be even less likely since both supports are also focusing the adcs - making the engage last fewer turns.
I'm fully aware all this will chance once you factor in ganks, bursts, etc. I just wanted to review a pretty common scenario.
My calculations (if correct) shows that the early game would favor the armor adc - but i do understand the importance of building the Infinity Edge first. I just think getting the early kill(s) - if the armor adc succeed in capitalize on his advantage - probably would put you in a situation where you probably would still get there first, and this time also wearing a chain mail?
Am i missing something or are adc just blinded by a lust for more damage?
BTW, i main support, which is why i probably don't get the adc mindset...