Implementing Cost Control Strategies
Work the levers in order
Eliminate waste, then rightsize, then commit, then re-architect. Waste: idle load balancers, unattached EBS volumes, old snapshots, non-production resources running nights and weekends, forgotten Elastic IPs. Rightsize with Compute Optimizer and Cost Explorer recommendations. Commit with Savings Plans or Reserved Instances on the stable baseline only, never on the peak. Re-architect with Graviton, serverless, and Spot for interruption-tolerant work.
Commitments
Compute Savings Plans are the most flexible and apply to EC2, Fargate, and Lambda regardless of family, Region, or OS. EC2 Instance Savings Plans trade flexibility for a deeper discount within a family in a Region. Standard Reserved Instances are zonal or regional, with regional RIs giving AZ flexibility and size flexibility within a family. Spot is the cheapest and can be reclaimed with a two-minute interruption notice, so it suits batch, CI, and stateless workers. Database and analytics services have their own reserved capacity options and are not covered by Compute Savings Plans.
Visibility and allocation
Budgets with alerts, Cost Anomaly Detection, cost allocation tags enforced through tag policies, Cost and Usage Reports queried in Athena and visualized in QuickSight, and S3 Storage Lens for storage distribution. Consolidated billing aggregates usage for volume tier discounts, and showback converts the bill into team accountability.
Traps
Data processing charges, not just hourly charges, drive cost: NAT gateways bill per gigabyte processed, so use free gateway endpoints for S3 and DynamoDB and reconsider architecture that routes bulk traffic through NAT. Cross-AZ traffic is billed. Interface endpoints carry an hourly and per-GB charge, so the endpoint-as-cost-saver answer only applies to gateway endpoints. Lifecycle policies that transition everything to Glacier can raise retrieval bills.
Rule of thumb
Never commit more than the trailing steady-state baseline, and check whether the workload can be deleted, resized, or made elastic before buying a discount.