Feature monitoring for real-time machine learning is crucial to prevent "garbage in, garbage out" situations and ensure model accuracy. It involves monitoring feature values after transformation, as well as aggregations of features such as metrics or statistics. Common obstacles include volatile dependencies on analytics teams, computing and validating feature metrics, limitations of current tools, and understanding and detecting data drift. These challenges can lead to inaccurate predictions and suboptimal performance if not addressed. Feature monitoring requires regular assessment of data quality, handling temporal joins and align timestamps, performing metric compute at scale, and implementing validation rules that take action when necessary. Addressing data drift is a complex process that often requires advanced algorithms and visualizations.