This can be hard sometimes, but it is always recommended that you completely turn your watch off each night. This helps to preserve the battery beyond the 2-3 year lifespan. If you use your watch for sleep tracking, consider giving your watch a turn-off during some downtime during the day or when you return home from work. Let your watch rest for a few hours each day. I typically only use my watch's sleep tracking a couple of times each week just to get a grasp of my current sleep quality. I turn my watch off completely most nights of the week.