COST 1. How do you make sure your capacity matches but does not substantially exceed what you need?
For an architecture that is balanced in terms of spend and performance, ensure that everything you pay for is used and avoid significantly underutilized instances. A skewed utilization metric in either direction will have an adverse impact on your business in either operational costs (degraded performance due to over-utilization) or wasted AWS expenditures (due to over-provisioning).
Best practices:
 Demand-based approach Use Auto Scaling to respond to variable demand.

 Queue-based approach Run your own Amazon Simple Queue Service (SQS) queue and spin up/shut down instances based on demand.
 Time-based approach Examples: follow the sun, turn off Dev/Test instances over the weekend, follow quarterly or annual schedules (e.g., Black Friday).
 Appropriately provisioned Appropriately provision throughput, sizing, and storage for services such as Amazon DynamoDB, Amazon EBS (provisioned IOPS), Amazon RDS, Amazon EMR, etc.