> The most important metric to me was the sleep score and related components. I've noticed my performance (mentally and physically) is tied to sleep in a huge way. I was skeptical that it would capture sleep metrics accurately, but after about a year of use, I can say without question that the number it presents as my sleep score is a very good proxy of how good I feel throughout the day.

For so many things, the absolute number being correct doesn’t matter, what’s more important is having _a_ scale that iou can use to chart against whatever you want. A “sleep score” doesn’t need to be accurate as long as it’s measuring the same thing (and that thing is the correct thing). Calorie counting is the same - it doesn’t matter if I think my breakfast is 500 calories but it’s actually 600 - as long as I consistently enter it incorrectly and measure my weight, I know I need to reduce my portion size somewhere.