When replying to the thread, please state the type of watch you have so we can compare how long they last compared to other users. I have a 42mm Watch and I'm currently on the OS2 Beta 3 and I am very happy to say that on days without using the Heart Rate Sensor too much (no workout days), the longest it's gone is a good 29.5 hours; I did cheat a little bit by putting the Watch on airplane mode whilst I was in bed so when I woke up it only used about 11% battery - not bad for 8 hours! I can't wait to see if having native apps (OS 2 feature) will prolong the battery life due to lessening use of Bluetooth connection. For a realistic comparison, when I had my Watch on OS 1, it was lasting for about 26 hours anyway. How long does yours last?