Lesson from Adam Piotrowski's wroclove.rb 2025 talk: a pharma client's CTO left and the AWS billing/alert contact email went stale. When the Postgres version reached AWS's extended-support threshold, AWS started charging ~€10,000 per month as a surcharge for running the outdated version. Nobody noticed for about a year — roughly €100,000 burned — until someone spotted anomalous transfers and it took two hours to identify and fix. Moral: be proactive about cloud costs, document infrastructure so successor-free contacts aren't the only channel, and understand which parts of your code cost you money later, not just up-front.