I'd never buy a bluetooth headset refurb'd. No warranty and has been in someone's ear canal. Esp when a new one is just $20 more.
If this is refurbished by jawbone (and I believe it is), I would expect them to have replaced the ear buds at the least. They are one of the better companies in terms of caring for their customers and standing up for their products. Many people will agree with this based on how Jawbone handled the "UP" fiasco