Check the complete set and any shield-dependent effect.
Read the piece list for the exact armor type: heavy, light and robe versions can have different effects. Some bonuses explicitly require a matching shield. For example, the Dark Crystal heavy shield-defense bonus depends on the Dark Crystal Shield; do not grant that conditional effect from the armor alone.
A matching appearance or grade does not establish a complete set. Start from the specific heavy, light or robe entry and compare its listed pieces with your equipment. Keep the basic set effect separate from an optional shield effect. This is particularly useful when comparing two configurations: record what is actually activated, not every bonus shown anywhere on the set page.
The armor’s ordinary defense, the completed set’s effect and additional enchant effects are separate layers. Replacing one required piece can change the set benefit even if the replacement has more defense. Check the exact set and enchant conditions before valuing an upgrade; a single highly enchanted piece does not establish that the entire set meets an enchant threshold.