I would wager that earbuds are already an item that most people prefer not to buy a used version of...

There's more waste in an average American's day's worth of single use packaging than in one pair of earbuds, which is good for decades.

I buy pretty much everything used... but I probably wouldn't buy used earbuds. For sanitary reasons sure but also because they aren't usually durable enough to be worthwhile buying second hand. The wires (or the batteries) are usually worn by even light usage

They are usually corded so they don’t get trashed like pods