Model and generation
Newer and more commercially desirable models may have stronger resale demand, but model alone does not determine the final quotation.
Physical condition
Inspect headbands, ear cushions, hinges, earbud surfaces, charging cases, control buttons, charging ports, logos and plastic surfaces.
Battery and functionality
Battery health matters significantly for wireless audio. Typical checks include Bluetooth pairing, audio output, left and right channel operation, microphones, controls, Active Noise Cancellation, charging, application connectivity and multipoint features where supported.
Accessories and quantity
Charging cables, audio cables where supplied, carrying cases, original boxes, documentation and replacement tips can improve completeness. Bulk quantity changes the economics and logistics of a transaction.