Learn from a 26-minute conference talk at Data Science Conference Europe 2022 where Aid Ahmetovic shares valuable insights on tackling complex machine learning problems, specifically focusing on delivery time prediction. Discover practical approaches for handling unclear customer requirements and making strategic pivots when model results prove unpromising. Explore technical methods for ensembling classification models with confidence probability scores and determining optimal probability cutoffs. Gain perspective on the critical decision of when to stop model optimization by understanding key tradeoffs in the development process. The presentation, delivered in Belgrade, offers hands-on lessons from real-world machine learning implementation challenges.