PSA: Diminishing Returns and Effective Health
When you buy armor, you are reducing the amount of damage done onto you by a percentage amount. For example, when you buy 100 armor, you are effectively reducing the enemy's physical damage onto you by 50%. If you buy 200 armor however, you are reducing their damage by 66.6%.
"Hey, the first 100 armor I bought reduced a whole 50%, and the second only reduced 16.6%, is that a diminishing return?"
No. Well, if you want to be extremely technical, the reduction is diminishing, but its effects are linear.
"What"
Okay imagine you have 2000 HP and 0 Armor. Obviously, it would take a whole 2000 Physical Damage to kill you, right? Now imagine you have 2000 HP and 100 Armor. With that 50% reduction, you are now looking at tanking a whole 4000 Physical Damage before it actually kills you. Add another 100 Armor, and you are tanking 6000 Physical Damage before it kills you. In this hypothetical scenario, for every 100 Armor, you effectively gain an extra 2000 HP. This is Effective Health, the multiplication of your Armor and your Health.
There's less of a confusion if instead of looking at Armor as a Damage Reduction, it's a Health Multiplier. Instead of the reduction explanation I started with in the beginning of this post, think of Armor like this: Every point of armor is worth a bonus 1% of your HP. If you have 0 Armor, you have no bonus. If you have 100 Armor, that's +100% Health right there, effectively doubling the worth of your HP. If you have 200 Armor, that's +200% Health or 300% Health in total, tripling your HP's value. Try to keep this explanation in mind the next time somebody mistakenly thinks that stacking Armor has diminishing returns.
Note: While Armor does not have diminishing returns, please build health with your armor too guys.