Launch changes the questions.
During a build, teams ask whether a feature works. In operation, the questions expand: who can diagnose a failure, how can a change be released safely, and where is the system explained?
Thinking about those questions early helps shape a platform that can be supported by people who did not write every line of it.
Keep the structure understandable.
Clear boundaries, consistent naming and small, well-defined responsibilities make a system easier to reason about. A simpler architecture is often easier to operate than a collection of fashionable tools.
Record decisions where future maintainers can find them. Explain the constraints and tradeoffs, especially when the reason for a choice will not be obvious from the code.
Make recovery part of delivery.
A backup is only part of a recovery plan. The team also needs to know what to restore, who can do it and how to check the restored service. Practice the process before relying on it.
Treat runbooks, monitoring and handover as delivery work. The strongest launch leaves the people operating the product with enough context to move forward.