Airflow Scheduling: When to Use Cron Expressions vs. Asset-Based Triggers

Apache Airflow offers two primary scheduling approaches for data pipelines: time-based cron expressions and Asset-based triggers, each suited to different use cases. Cron scheduling runs a DAG at a fixed time regardless of whether upstream data has actually changed, making it predictable but potentially inefficient. Asset-based scheduling, introduced in Airflow 2.4 as Datasets and renamed Assets in Airflow 3.0, triggers a DAG only when dependent data has been successfully updated. Assets use the concepts of inlets and outlets to track what data a task consumes and produces, supporting data lineage, governance, and audit trails. Choosing between the two depends on whether a pipeline's dependencies are better described by time or by the availability of updated data.