What I’m taking away isn’t so much a finished product, but a clearer way to think about retention. Most fitness apps see users as individuals to convince. Tally Rally, on the other hand, sees them as part of a small group where each person’s absence stands out. This shift in perspective is the real contribution, and the prototype shows it’s possible to design for this, not just talk about it.

The toughest part of designing Tally Rally was not building the screens or the system. At every stage, there was pressure to add, decorate, and personalize even more. The real challenge was learning to say no to anything that didn’t help the team, and yes to the small, plain details that made the squad feel real. If the next version of this app keeps users for more than three weeks, it will be thanks to those details.