I use earbuds a lot - working, driving, at the gym - and they DO wear out over time. I don't want to shell out another $159 to replace something that was once included.

I have a cordless drill. It came with 2 batteries, because they know it makes sense to have one charging while the other is in use. I think the novelty of these wireless earbuds is going to wear off when they're about 5 hours old.