What Should I Set “Smoothing” To?

Increase Smoothing to have more consistent recommendations, and to “smooth” over small variances.

If you are the sort of person that gets over small setbacks like a poor night's sleep or a bit of a cold easily then increase the smoothing to ensure those small variances are not reflected in the chart and recommendations. This will also work in the other direction, meaning if you have a good night's sleep the recommendation is less likely to increase so much in the morning.

Decrease smoothing to have more responsive recommendations to small changes.

Alternatively if, like me, you are older and a poor night's sleep following a few G&T’s the night before can knock you sidewards for a while, then consider reducing the smoothing value so the chart reflects those things more frequently. But bear in mind this will also increase the likelihood of a good night's sleep meaning a “push hard” recommendation.

Generally I personally (a 55-year-old male) find around 2 or 3 as a good setting for me.