Interesting angle with the social nudging. I built Momentum (momentumfit.app) for sustainable fitness habits — AI-adjusted weekly movement plans that adapt to real-life constraints rather than punishing you for missing a day.

My experience: the habit apps that retain users aren't the ones with the best streaks or social pressure. They're the ones that gracefully handle failure. When someone misses three days, the worst thing you can do is show them a broken streak. The best thing is to regenerate their plan around what's actually realistic this week. That "recovery" moment is where long-term users are made.