Standardize the cross-cutting concerns
Audit metadata, error responses, correlation identifiers, outbound HTTP configuration and security conventions should behave consistently across services.
A small set of focused starters or shared modules reduces duplication and simplifies operational support.
Keep business ownership local
Shared components should provide defaults and extension points, not centralize business rules. Teams need the ability to override policies without forking the platform.
Treat adoption as a product
Versioning, migration notes, examples and compatibility tests are essential. The best shared component is one that teams can understand and upgrade safely.