Watch only mode on the Gear S3 (and Gear Sport) can extend battery life by 40 days! - SamMobile
Just replaced my Gear S3 battery (24$ + 10$ for tools). Excited to get 3+ days back. Links in comments, will report back with new battery life in a few days. : r/GearS3
Samsung Gear S3 users reporting poor battery life post Tizen 3.0 update - GSMArena.com news
Samsung Gear S3 battery drain problem fixed with latest update - PhoneArena