Terraform Module Refactoring - Decision Expert

Assumption: You know Terraform syntax. This covers when to modularize vs keep inline.

NEVER

• Never modularize on first usage — wait for the third real instance; premature abstraction locks in the wrong seam.
• Never expose module variables 1:1 with resource arguments — that's not abstraction, it's indirection (the Leaky Abstraction trap).
• Never refactor inline resources to a module without running terraform state mv first — Terraform will plan to destroy and recreate every resource.
• Never create a module for frequently-changing code — module API changes cascade across all consumers.
• Never skip terraform state pull > backup.tfstate before any state migration.

The Core Decision