I've read that sleep is tracked automatically, but in the app there's a "begin sleep now" button

[Korasi]

I'm confused, if my fitbit tracks my sleep automatically, why is there an option to manually tell the app I'm going to sleep? Does that mean the automatic feature isn't as accurate? Which one should I be using? I don't understand why both options exist if one is better than the other.

thanks

[JohnnyRow]

Better to use the automatic sleep sensing.  I think the 'begin sleep now' was, and still is, for a few models that don't have heart rate monitors to help detect sleep and stages.  And according to the Help sleep section, using 'begin sleep now' can prevent getting sleep stages detected.  I suppose one could argue that option should not even show, depending on which tracker is connected.

There is one thing I have found it useful for however, though not officially recommended by Fitbit, is to get credit for naps of less than an hour.  Fitbit will not automatically detect any sleep less than one hour.