Trusted Advisor covers five main areas, and it is designed to give you some guidance around what are considered the best practices for your cloud deployment. The areas that are covered are as follows:

• Cost optimization
• Performance
• Security
• Fault tolerance
• Service limits

It's available to everyone and free to use for basic coverage. If you are paying for Business- or Enterprise-level support with AWS, you get access to additional checks that are important for production workloads. At the time of writing, there are 53 checks for cost optimization, performance, security, and fault tolerance, and 48 separate checks for service limits.