Have batteries actually ever FAILED in wireless headphones? Sure, they degrade and charge becomes lower, but I've never had them outright fail. A headphone that lasts my 2-3 hours of commute/daily use is completely useable, even if it's original charge lasted 5 hours.

Cables do fail though, completely. They become unusable.

In my entire life time of using headphones/earbuds since school with the PSP, ALL wired options have failed after 1-2 years for purely mechanical cable reasons. Not a single wireless failed for electronic reasons. The did fail for me dropping them and stepping on them reasons, though.

My sennheiser earbuds are now down to 15 minutes of battery life. Less if it's a cold day. Sure, they're not completely dead yet, but they're effectively useless. And it's not like I can easily replace the batteries. Most wired earbuds or headphones at a similar price point have replaceable cables.