AWS Savings Plans vs. Reserved Instances: Which Delivers the Biggest Savings?

As organizations scale their use of AWS services, managing cloud costs becomes increasingly important. AWS provides two main methods for long-term cost optimization: Savings Plans (SPs) and Reserved Instances (RIs). While both offer significant discounts compared to On-Demand pricing, each has its own benefits depending on your business needs.

So, how do you choose between these two options to maximize your savings? Let’s explore the key differences between AWS Savings Plans and Reserved Instances, and find out which one might be the right fit for your cloud environment.

Savings Plans vs. Reserved Instances: Key Differences

When Are AWS Savings Plans Most Effective?

AWS Savings Plans are an excellent option for businesses with dynamic cloud environments that need flexibility. Here are the scenarios where Savings Plans are particularly beneficial:

1. Evolving Workloads with Changing Demands

If your business faces frequent shifts in workload, whether scaling up during certain periods or adjusting based on project needs, Savings Plans allow you to stay flexible. You don’t have to commit to rigid instance types or regions, giving you the freedom to adjust as your usage evolves.

2. For Modern Serverless and Container Workloads

If your infrastructure relies on services like AWS Lambda, Fargate, or SageMaker, you’ll find that Savings Plans are a better fit. These newer technologies often require adaptability in compute usage, something Reserved Instances can’t offer. With Savings Plans, you get savings while working with cutting-edge, serverless applications.

3. Supporting Global Operations

When your applications run across multiple AWS regions, Savings Plans enable you to scale across geographies without sacrificing savings. The ability to apply a single plan to multiple regions helps organizations manage their global infrastructure in a way that Reserved Instances can’t.

4. Simplified Cost Management

Savings Plans automatically apply discounts to your usage, making cost management straightforward. Unlike Reserved Instances, which require matching usage with specific configurations, Savings Plans eliminate the complexity and let you focus on your work rather than worrying about exact matches.

5. Handling Workload Spikes with Ease

For organizations that see sudden surges in demand, Savings Plans can provide the flexibility to handle these spikes without overcommitting. Whether it’s a seasonal business or an unpredictable demand cycle, Savings Plans let you scale freely within your committed amount, ensuring that you stay cost-efficient during peak periods.

Benefits of AWS Savings Plans

• Easy Integration: Works smoothly with EC2, Fargate, and Lambda for flexible cloud management.
• Automatic Discounts: Savings are applied automatically, ensuring you get the best value.
• Simplified Management: Streamlines reporting and commitment tracking for easier cost management.

When to Use Reserved Instances?

• Predictable, Steady Workloads: Reserved Instances (RIs) are ideal for applications with consistent usage, such as databases and web servers. When matched to your exact usage, they can save up to 75% compared to On-Demand pricing, perfect for "always-on" services.
• Specific Instance Needs: For workloads requiring fixed instance families, sizes, or configurations (like Amazon RDS or Redshift), RIs allow you to lock in those exact specifications, ensuring reliability and consistency.
• Broad Service Coverage: RIs cover not just EC2 instances but also services like Amazon RDS, ElastiCache, Redshift, OpenSearch, and DynamoDB. This makes RIs suitable for teams managing diverse infrastructure and services across AWS.
• Capacity Reservation: If your application needs guaranteed capacity in a specific Availability Zone, Zonal RIs can ensure high availability and are essential for workloads with strict uptime or compliance requirements.
• Long-Term, High Utilization: For applications with predictable, sustained demand, committing to a 1- or 3-year term can maximize savings—especially if the workload uses at least 75% of the Reserved Instances during the term.

Benefits of Using Reserved Instances

• Predictable Savings: Save up to 72% compared to On-Demand pricing with a long-term commitment.
• Better Control: Gain more control over instance usage and allocation for consistent workloads.
• Convertible Options: With Convertible RIs, you can change instance families or operating systems to meet evolving needs.

Payer vs. Linked Account: Purchase Strategy for AWS Savings Plans and Reserved Instances

Blended Strategy Example

A Central FinOps team purchases Savings Plans for shared EC2 and Lambda usage, while the data science team buys RIs for SageMaker instances to ensure precise cost allocation.

AWS Pricing Models

Aligning workloads with appropriate AWS pricing models helps optimize costs while also providing AWS with clearer signals for future compute demand. This contributes to improved capacity planning, more efficient infrastructure management, and enhanced sustainability.

AWS Cost Management Tools

AWS offers a suite of tools to support RI/SP decision-making and management:

Conclusion

Selecting the right AWS pricing option is more than just about cutting costs; it's about aligning with your business needs, workflows, and technology plans. Both AWS Savings Plans and Reserved Instances offer flexible choices, allowing you to pick the best fit for your organization.

Need assistance with building a purchase strategy, analyzing coverage, or setting up tools like AWS Billing Conductor (ABC)? Reach out to us, share your use case, and TekBay will help craft a personalized SP/RI strategy tailored to your needs.