Should I close an unused AWS account or let it become suspended?

I’d formally close it after checking every region for running resources, storage, snapshots, reserved capacity, and other billable items. An unused account can still accumulate charges if something was overlooked, and resolving an unexpected bill later may be more trouble than closing it now.

Keeping an older account in good standing may be useful if you expect to use AWS again, since newer accounts can have service and quota restrictions. But there’s no reason to preserve an account you definitely won’t need; close it once you’ve confirmed the account and all regions are clean.

If you might use the account again, you can keep it open, but secure it carefully: remove unnecessary resources, enable billing alerts, apply least-privilege access, and set a budget notification. A budget can alert you when spending reaches a threshold, but it isn’t always a hard spending cap, so it shouldn’t replace cleanup.