What Terraform practices would you standardise across a team?

Good Terraform practice is mostly about making change safe and legible. A new engineer should be able to see where an environment lives, how state is stored, which module owns a resource, and what a plan will change before approving it.

terraform {
  required_version = "~> 1.9.0"

  backend "s3" {
    bucket       = "acme-tfstate"
    key          = "prod/app/terraform.tfstate"
    region       = "us-east-1"
    encrypt      = true
    use_lockfile = true
  }

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.60"
    }
  }
}

A practical checklist

• One state per environment and blast-radius boundary
• Small modules with explicit inputs and outputs
• Remote state with encryption, versioning and locking
• Pinned Terraform, provider and module versions
• fmt, validate, policy and plan in CI, with approval before apply
• No secrets in code, tfvars or state where avoidable
• Documented ownership and a rollback or recovery path

Standardise the boring parts so reviewers can focus on intent. A repository template with backend configuration, CI, tagging and module conventions removes repeated decisions. Enforce the non-negotiables automatically, and leave style preferences to formatting rather than review comments.