The NAT Gateway story is a classic, and the reason you reached for Terraform is honestly a better motivation than most tutorials give. Wanting terraform destroy to be sure nothing is left running is exactly the habit that saves people from the next surprise bill. One thing that pairs well with it: an AWS Budgets alert set to a small amount, so a forgotten resource shows up in your inbox after a day instead of at the end of the month. Good luck with the next stage of EVI.