Stack

From NWNWiki

Stacking is the concept where more than one instance of the same type of effect is cumulative, possibly up to a cap. The rules that determine when things stack are somewhat haphazard, with many exceptions. Some of these take into consideration the source of an effect.

Examples of things which do stack:

• Ability score bonuses stack up to +12.
• Armor class bonuses of different types stack.
• Dodge bonuses to armor class stack up to +20.
• Saving throw bonuses stack up to +20.
• Skill bonuses stack up to +50.
• Damage immunity stacks.

Examples of things which do not stack:

• Armor class bonuses of the same type, other than dodge, do not stack.
• Multiple uses of the same spell, such as bull's strength, do not stack (but the spell does stack with the bull's strength feat).
• Concealment does not stack.
• Damage reduction does not stack.
• Damage resistance against the same type of damage does not stack (except for resistance from feats).