LONDON—The booming market for secondhand luxury goods is creating a dilemma for makers of high-end handbags, fashion and jewelry: Join the trend, or ignore it. Secondhand luxury isn’t new, but its popularity is surging. Steep price hikes by prestigious brands like Chanel SA are driving some luxury buyers to look for less expensive used items. Others are seizing on secondhand goods’ sustainability bona fides: A used pair of designer jeans doesn’t cost any more of the planet’s resources to make.

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