22 years old. $160K/month. One year in. But the app isn’t the secret, it’s how he decides what to build. Meet Mauro. He built Symmetry, a gym tracking app that’s now one of the biggest names in the Spanish fitness market. He went through 3 phases: Phase 1: build what we wanted. Terrible. Phase 2: build what users asked for. Mediocre. Phase 3: treat every feature like a science experiment. $160K/month. His system: Set ambitious quarterly OKRs (easier to move metrics when you’re new) Track downloads, activation, retention, ARPU Start from a problem, not a solution Write hypotheses, then A/B test everything for 2+ weeks Kill what doesn’t move the needle, double down on what does One example: adding a single screen at the end of a workout increased retention by 3%. Meanwhile two full redesigns of the home screen moved nothing.