The AWS Well-Architected Framework provides architectural best practices across the five pillars for designing and operating reliable, secure, efficient, and cost-effective systems in the cloud. The Framework provides a set of questions that allows you to review an existing or proposed architecture. It also provides a set of AWS best practices for each pillar.
The architecture of a workload changes over time, and Well-Architected reviews should be applied at key milestones in the product lifecycle. For example, early on in the design phase to avoid one-way doors that are difficult to change, and then before the go live date. Post go live your workload will continue to evolve as you add new features and change technology implementations. You’ll need to follow good hygiene practices to stop its architectural characteristics from degrading as you evolve it. As you make significant architecture changes you should follow a set of hygiene processes including a Well-Architected review.