How much armor penetration is enough?

[Cockpuncher]

I know, you cannot have enough of armor penetration ;). But how much is 'optimal' for all hexes in endgame?

Currently I'm using only devil card for my rapier for a total of 220 AP. Could sacrifice some damage output and put some beast cards. Would be worth it? Does someone run some testing? Is it worth to increase AP at the cost of lowering overal damage output, let's say 1 wildcard for 2 beasts?

To be precise I'm using crit-based overdrive build mostly and can also deal damage through frequent shockwaves, but in terms of dealing damage to load overdrive, would increased armor penetration help?

Also what you consider decent armor penetration for 'universal' builds?

[Kilivan Jg]

okay. as a guy who uses swords and shotguns (both which have low damage) you NEED 120 base armor pen. all monsters have 120 with hexes on and its a must have. the next teir of AP would be 180-240 with 240 most monsters you come up agaisnt youll be dealing your base damage agaisnt. then from there on out theres the monsters with armored buff and its alittle overkill to run anythign above 240 as these armored monsters arent common.
overall 120 armor pen is needed, 240 is probably the highest you realistically need

[Giallo]

Bit necro, but may be useful:

as armor represents chance to negate damage, it's important to have AP, armor penetration, as much as to nullify Armor of enemy. Armor is calculated as a Logarithm, meaning that with small numbers of armor a proportionally large quantity of chance to deflect is rewarded. Increasing armor has diminishing effects on that chance. If AP is just subtracted from Armor value of target, then it means that the less AP you have in respect of target Armor, the less it will reduce as well the chance of deflecting attacks. As AP number approaches to total Armor of target, it is more influencial. Let's say two enemies have 190 and 280 armor respectively. With 1 beast card, you reduce first armor from 190 (50,5% deflection chance) down to 100 (36,1%), so cutting by 14,4% deflection chance. For monster number 2, armor goes from 280 (60% deflection chance) to 190 (50,5%), reducing deflection chance by 9,5% only.
That said, from my game experience in hardmode, every enemy has at least 120 Armor (40% chance of deflection), tough enemies have from 170 to 230 (47% to 55%), bosses and champions have from 220 to 290 (up to 60%). Very few monster with more than 290 armor, so not needed to go over 290 AP.

Those values of armor are just my game experience, experienced players can tell a different&realistic story.

Also, considering attack speeds of weapons, rising AP as high as possible can be crucial. You don't want to waste your hammer attack after have being hit 3 times, don't you?

As for formula to calculate chance of deflection in respect of armor, look at this discussion

[Cockpuncher]

Thanks for detailed info. But still considering ~200 AP as optimal. Just interested if someone played more with, let's say, over 400 AP and how were the results. It could increase damage output but for the cost of sacrificing something else. And I wonder if it's worth it...