“The two areas — the biggest mistakes: under-trying to understand the size of the market you're addressing… and not understanding what the ongoing costs of an app are going to be… if I get any amount of volume I'm suddenly spending thousands of dollars a month supporting this app.”

Apps Fail for Two Reasons: Market Too Small or Ongoing Costs Not Modeled

David's post-mortems on 50 failed apps consistently trace back to two errors: an audience too niche to sustain a business, and backend costs that scale faster than revenue. Subscription infrastructure didn't exist for most of his weather app's life — so what should have been a SaaS was inadvertently running as a charity.