Today my Bose headphones drained its battery about halfway in only about 1 hour. It used to last well over 15 hours. It was a sign that the battery was on its way out.

Officially, it costs $259 + $100 shipping to have Bose replace the battery. These headphones cost $300. Ridiculous. I couldn't find any batteries for this online and customer support said the battery is not user-replaceable.

This guide shows disassembly down to the battery.

Tools required: Thin bladed phillips screwdriver, plastic or wood spudger when handling battery, small flat blade screw driver. Micro-screwdrivers will work fine.

Beware of ESD (static electricity). When you open electronics not all parts will be protected from ESD. This can kill some/all of your device. Do not work on/over/near rugs and fuzzy things. Do not wear fuzzy clothes. Discharge yourself to a large metal object before working. Recommended: grounding mat and wrist strap. Can also work naked.

ESD: You can even work naked or almost naked to reduce risk of clothing ESD. I'm not kidding. Obviously do not remove clothing in public...