The watch loses time up to sometimes 90mins in any 48hr period regardless of whether it is worn or not. It loses time by up to 15mins when i take  it off at night and resume wearing it after no more than 8 hours. And if you don't reset the time it will continue to lose time. I bet if I didn't reset the time each time time it fell behind it could lose time by several hours. Very unreliable and very disappointed.