Managed Iceberg compaction in S3 Tables removes real operational work, but it will not tell you when it stops. A practical look at the maintenance jobs that fail silently, the retention cascade that keeps superseded data on your bill for two weeks, how compaction charges actually accumulate, and the handful of knobs worth touching.
SageMaker Lakehouse is built on the Glue Data Catalog and Lake Formation, so a migration barely moves data. It moves enforcement. Here is the failure mode that bites, the cost levers that actually change, and a decision procedure for working out whether the move is worth it at all.
CloudWatch rarely fails loudly, it accumulates. This is a breakdown of the four independent meters behind the bill: ingestion, storage, Logs Insights scans and custom metric cardinality. Why the same log line gets billed three times, why log groups never expire by default, how a single dimension can multiply your metrics bill without your traffic changing, and how to attribute the spend to specific log groups before you start deleting things.
Your lake bucket keeps growing even though nobody added data. Here is where the bytes actually sit: snapshots you never expired, orphan files no metadata points at, metadata JSON accumulation, and the object store's own hidden inventory. Plus the safe order to clean all four up.
Tagging a resource and activating a cost allocation tag are two different operations, and AWS never tells you when you have only done the first. A practical guide to the activation gap, what backfill can and cannot repair, the five places coverage leaks, and a retrofit order that actually converges.
One checkbox can reprice every output in a MediaConvert job. A working breakdown of how the per-minute charge is assembled from normalized minutes and per-output billing, why failed jobs are free but still expensive, and how to build retry and recovery that classifies before it retries.
Before I quote AWS work, I run a read-only account health check: six passes covering identity, logging, region sprawl, infrastructure code, cost shape and support escalation. Here are the commands, the pass tests, and the findings that change the number.