Which of these stack?

[Matamane]

Does an enhancement bonus to Natural Armor and an enhancement bonus to Deflection stack? I think so, because they enhance different things

What about bracers of armor and robe of the archmagi and mage armor? I think not, but because they are different sources, maybe.

[ranagrande]

The first two do stack, because a Natural Armor bonus to AC stacks with a Deflection bonus to AC. That you have enhancement bonuses to both doesn't matter. However, if you had more than one thing that granted an enhancement bonus to Natural Armor or Deflection, the enhancement bonuses would not stack.

The bracers, robe, and Mage Armor spell do not stack, because they all provide an Armor bonus to AC.

[Gorbash]

1. They stack, it's not the same type of bonus.

2. They don't, it's the same type of bonus.

[Moriato]

Does an enhancement bonus to Natural Armor and an enhancement bonus to Deflection stack? I think so, because they enhance different things

What about bracers of armor and robe of the archmagi and mage armor? I think not, but because they are different sources, maybe.

Natrual and deflection? Yes, they are different types of bonuses.

Bracers of armor + robe + mage armor, no.

It doesn't matter what the source of the bonus is, only that the bonuses themselves are of different types.

Edit: Predictably ninja'd. One interesting note about natural armor bonuses, though, is that enhancement bonuses to natural armor (such as from an amulet of natural armor) stack with a creature's "inherent" natural armor, just like if you were putting an enhancement bonus on normal armor.

[ghashxx]

Yep, they all stack. It's all about what kind of enhancement (armor, nat armor, deflect, divine etc) you're looking at. Two enhancements of the same type don't stack, otherwise you're all good.

[ericgrau]

Enhancement bonus to X increases X. Then you worry about stacking after that point... as long as we're not talking about two enhancement bonuses to X. That doesn't stack either.

So if you have a +1 chain shirt (total armor bonus +5) and bracers of armor +3, your armor bonus is simply +5. If you also have a +1 heavy shield (total armor bonus +3), then you have a +3 shield bonus which stacks with the +5 armor bonus for a total of +8 to AC.