I don't understand sleep ratings of good and fair

[ratfancy]

I can relate to this post: https://community.fitbit.com/t5/Charge-6/Charge-6-Daily-Readiness-99/m-p/5724540

Sometimes I can get 5.5 hours of sleep with 40 minutes deep and it says I slept Good.  Why?  The duration is not long enough.
Other times I will get 7.5 hours of sleep with maybe 30 minutes of deep sleep and it says Fair.
What are the benchmarks for getting Good sleep?

[LZeeW · Accepted solution]

@ratfancy   Here is a link to Fitbit’s Help article  with the relevant section expanded for you.  Duration is one part of the score (50%), deep and REM are another (25%), and there is a restoration component (25%).  The restoration looks at tossing/turning and your sleeping heart rate.  Premium members see the full breakdown and it makes the sleep score make more sense.  But Premium is pretty pricey for just this feature.