If you follow cost optimization best practices, you should have a good cost comparison with existing activity. It's always possible to reduce the cost of your applications that are migrated and matured over time. Cost optimizations should never end until the cost of identifying money-saving opportunities is more than the amount of money you are going to save. Until that point is reached, you should continually monitor your expenditure and look for new ways to save on cost. You should keep finding an area to save costs by removing idle resources.

For an architecture that is balanced in terms of its cost and performance, ensure that the cost paid for resources is well utilized and avoids any significantly underutilized IT resources such as server instances. A biased utilization metric showing exceptionally high or low cost will have an adverse impact on your organization’s business. 

Application-level metrics for cost optimization need to be considered carefully. For example, introduce archival policies to control data storage capacity. To optimize the database, you should check for appropriate database deployment needs, such as if multi-location deployments for the database are really necessary or whether provisioned Input/Output Operations Per Second (IOPS) are applicable as per your database utilization needs. To reduce your administrative and operational overhead, you can use the SaaS model; it will help your employees to focus on applications and business activities.

To identify a gap and apply necessary changes for cost-saving, you should implement resource management and change control processes during the project life cycle. Your goal is to help your organization design the architecture as optimally and cost-effectively as possible. Keep looking for new services and features that might directly reduce your costs.