This inefficiency occurs when an EC2 instance remains in a running state but is not actively utilized. These instances may be remnants of past projects, forgotten development environments, or temporarily created for testing and never decommissioned. If an instance shows consistently low or no CPU, network, or disk activity—and no active connections—it likely serves no operational purpose but continues to generate ongoing compute and storage charges.

Workloads are sometimes deployed in specific AWS regions based on legacy decisions, developer convenience, or perceived performance requirements. However, regional EC2 pricing can vary significantly, and placing instances in a suboptimal region can lead to higher compute costs, increased data transfer charges, or both. In particular, workloads that frequently communicate with resources in other regions—or that serve a user base concentrated elsewhere—can incur unnecessary costs. Re-evaluating regional placement can reduce these costs without compromising performance or availability when done strategically.

EC2 instances are often overprovisioned based on rough estimates, legacy patterns, or performance buffer assumptions. If an instance consistently uses only a small fraction of its provisioned CPU or memory, it likely represents an opportunity for rightsizing. These inefficiencies persist unless usage is periodically reviewed and instance types are adjusted to align with actual workload requirements.