Bought this July 25 for about $20. By September 10, the watch could only hold a charge for one day. At 6am, it was at 100%. By 4:15pm, the charge was at 43%. By 6:30pm, the charge was down to 18%. This isn't enough charge to wear overnight to utilize the sleep mode. Just to be sure, I tracked it again the next day. By 9pm, charge was down to 12%. I'm keeping it to use the other attributes but I'm disappointed that all the boasted description of the watch's perks are not true. Ah, well. It's still not bad for $20 to measure other bio stats.