An accessory changes the read of an outfit because it sits at a point the eye naturally checks: wrist, waist, face, hand, shoulder, or foot.
Decide what needs finishing
A belt can resolve the waist. A scarf can introduce colour near the face. Jewellery can control emphasis. Eyewear can change facial geometry. A bag can alter the proportion of the entire silhouette.
Use hierarchy
When the bag is strong, jewellery can become quieter. When the earrings lead, the neckline should give them room. When the belt carries visible hardware, other metal should relate without competing.
Function still matters
A handbag must carry what the day requires. Sunglasses need proper fit and appropriate lens protection. A bracelet should not interfere with movement. An accessory that fails its task becomes styling theatre.
Ignore promised resale
Secondary-market value varies by condition, demand, provenance, and timing. Buy accessories for material, use, and wardrobe fit first.
THE GRAY CRAB view: the accessory is not the final flourish. It is one of the decisions that makes the outfit coherent.