You Can Not Measure What You Do Not Care To Manage When I started my first data scientist job in 2015, the team I joined had a recommendation system that would run every night to compute new recommendations for all users of our platform. This was the easiest way to handle the cold start problem. At the next company I worked at, we had a rule that every machine learning model must be setup to automatically retrain (“autoretrain”) on fresh data on a periodic basis.