How long will the battery on a samsung galaxy gear smartwatch last?

Samsung Galaxy Gear Reference Manual

you have to remove the contacts via gmail.

You can update the OS from Android to Tizen. Once you are running Tizen, you will have a lot more features, but you can not install apps that are not in your S3Gear app.

try pressing the power button for 3 to 5 secs. If still no power, connect it to a working usb/power source and try to turn on again.
If no sign of power even connected, you might need a battery replacement. A little history on what happened before this will be helpful

From your samsung phone, select the apps that will be shared with your smartwatch

Seems like the charging capabilities of the battery have been exhausted.
Try another cable/ac adapter. If same results, you might think of a possible battery replacement

Depending on what you are using the watch for it will have different battery life. Using the talk feature you should get around 2 hours, on standby about 7 days, the analog watch has a seperate battery that should last 2 years and charging the watch takes 2 hours to get a full charge.

Yeah, the samsung galaxy gear smartwatch has a camera. It's 1.9 MP.