A team observes that disk usage on their CI runners grows continuously across builds despite each individual build cleaning up its own containers.

Even disciplined per-build container cleanup doesn't address accumulated images, build cache, and volumes left behind across many different builds over time — recommend a scheduled `docker system prune -a --volumes` (or equivalent CI-runner-level cleanup job) run periodically/between builds, separate from any in-build cleanup steps that only address that specific build's own resources.