Like many women, 32-year-old Brett Heyman kept a collection of glittering trinkets tucked away in a corner of her closet, some that were gifts from her husband or mother, others that she'd bought for herself. But after having children and launching a business, Ms. Heyman found the dangling gemstone earrings and clanking bracelets no longer matched her "boring uniform" of jeans and a blazer.

In a fit of therapeutic spring cleaning, Ms. Heyman pared down her wardrobe, sorted through her unworn baubles, marched in to a Manhattan...