EDIT: It would appear that you can also run 5 armor pen marks, 4 flat ad marks and 1 flat ad glyph to have the same bonus ad as the 4 percent lifesteal page. (You still run flat ad quints) Noone would know you were running armor pen and not lifesteal, unless they looked you up.

As Season 4 is picking up speed, I am predicting 6 armor penetration reds, 3 flat ad reds and flat ad quints to become the standard for ad carries once again. These runes were seen as optimal at certain points in time and indeed, it was not uncommon for certain players to run armor pen reds AND quints. As we come to a point where everyone is hitting high amounts of armor late game the similarity to flat damage in the early game and reliability in the late game make armor pen much more attractive these days.

Let's say you even get outlaned by someone with 2 lifesteal quints and you can't justify dropping the lifesteal for early game. The fact is there will always be a most optimal choice for every game and if you get used to armor pen reds and flat ad quints, that may just be the best option for you.

The start for ad carries with armor pen is still going to be dorans blade, but you can run longsword if you prefer the 3 pots.

Everyone builds BT or BORK first now anyway, so I feel like the 4 percent lifesteal and flat ad are kind of wasting the potential of your runeset. Crits hit harder with armor pen runes, attack speed becomes more valuable and lifesteal quints don't do anything to make you hit harder. You can skirt around them and in fact, I think it's a better rune choice for the current ad carry role except that you lose a little bit of flat ad (about 4) to your rival (which also means less damage on towers).

In my opinion, it's worth the tradeoff because you only really feel it early game. Your lifesteal scales with the damage you deal so if you want to compare your 4 percent lifesteal page to an armor pen reds page when you both have bt you will notice that the damage and lifesteal are very similar.
Forget for a second that you lose a bit of lifesteal, you DEAL MORE DAMAGE with this setup because you have about 1.2 less flat ad than someone running 10.8 flat ad and 4 percent lifesteal, but you have 7.7 more armor penetration than they do. You also get access to health regeneration in the defensive tree this season which is not always the case, so you don't feel the loss of lifesteal as badly.

You can also tell your support to pick someone with sustain, and if you have this page set up you will have an advantage for those situations. I run feast on my ad carries, so I don't actually feel much of a difference without it and can catch people off guard with this rune page.

Here is winrar's article about armor penetration changes in season 3:
http://www.reignofgaming.net/blogs/a-different-view/vvinrar/22582-the-effect-of-season-3-penetration-rune-changes-on



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