Easily 4-5 days without recharging, with consistent use throughout the day. Official estimate is 25 hours of continuous use, I get around 20.
I just charge my headphone where I charge my phone, and never worry about batter life. Even if battery is reduced to 50% capacity it wouldn't affect my usage.
Meanwhile, 20 hours would be irritating to me on long days, and 10 hours (probably a few hundred cycles/less than a year) would interrupt my work and concentration daily. Just goes to show how the inconvenience varies between people.
I just charge my headphone where I charge my phone, and never worry about batter life. Even if battery is reduced to 50% capacity it wouldn't affect my usage.