Do these all work together seamlessly, and in conjunction with each other. For instance, if the watch doesn't pick up some steps for some reason, but the iPhone does, will the watch pull the missing steps from health and add them to the step fitness totals for Activity? Second, I have switched to using Activity for tracking all of my runs. However, I still manually enter the runs into Nike+ running, as that has all of my historical run data for several years, my friends are on there, etc. I've noticed that the watch and Nike+ both write to Health for the same run. I could revoke Nike+'s Health writing privilege. But is there any harm or chance of improper stats if I continue to allow Nike+ to also write to Health - do I have to make sure when I enter my runs into Nike + that the exact date and time are accurate?