Once I received these, I used them a lot for 2 months. Listened to books on tape and music, while commuting and for workouts almost everyday for long time periods. They sound really really great, especially for the price! Unfortunately, at just around 4 weeks of having them, they stopped holding a charge. If they were plugged in via USB to my computer, I could turn them on and pair to my iPhone 6, but once unplugged from the USB, they were dead. So they became useless. I contacted their customer support through the Merkury Innovations website. They emailed me back within 2 days and said to just take a picture of them, and give my mailing address and they would replace them at no cost. I'm waiting to receive my second pair in the mail. I'll let you know how it goes!