One norm that comes to mind is 10,000 steps as an activity goal. It's pretty clear that was just a round number that happened to be just outside the realm of many people's everyday activity. So reaching it was an achievable stretch. But it wasn't clear what hitting that goal was supposed to mean.
I remember seeing a flurry of articles earlier this year suggesting that the benefits (cardiovascular, I assume) dropped off after 7,500 or 8,000 steps. But that's population level and doesn't incorporate cadence.
These targets can be a challenge for some people with chronic conditions. At QS13, Jackie Wheelwright had a talk on figuring out what a good step target would be for her, that wouldn't leave her with days of fatigue. I believe she landed on a number around 4,000.