How many of you are measuring oxygen saturation?

I don’t see the merit in it. You have to have a pretty advanced watch to track it, and even then there’s no guarantee on accuracy. I check mine intermittently with a pulse ox only because I have one for work. I don’t see it adding any value to my training metrics though.

My watch does it, but I never look at the data. I largely would only be interested if I was doing an activity at altitude, and for me that would largely be backpacking.