If they add a PCB and switches but no case, prompt a compatible case and mounting screws with a one-click bundle discount. If they linger on premium switches, offer an optional lubing kit and foam dampeners; if they remove a keycap set, suggest an alternative colorway or PBT upgrade. Use urgency when stock is low and show estimated assembly time for novices. For returning customers, surface past preferences to prefill recommendations. Track conversions and microbehavior to continually refine which combos feel helpful versus pushy.