The summary.
SET BILLING ALERTS BEFORE PROVISIONING ANYTHING
At a figure you expect and a figure that would alarm you. Investigate immediately when one fires.
WHAT CAUSES SURPRISE BILLS
Resources provisioned and forgotten, test environments left running, scaling in response to bot traffic, and stolen credentials used to run someone else's workloads at your cost.
That last one is a known and costly attack. A second authentication step on cloud accounts prevents it.
THE MOST COMMON WASTE
Over-provisioning. Right-size resources rather than guessing large.
Tag everything, or resources become unremovable because nobody knows what they do.
REVIEW THE BILL MONTHLY, IN YOUR OWN CURRENCY
Foreign-currency billing means your cost changes without the provider changing their price.
ON SUBSCRIPTIONS
Review annually. Per-user subscriptions frequently include people who left.
Diarise renewal dates with their notice periods.
ON OWNERSHIP
Business services registered to the business, on a business address, with more than one administrator.
An account registered to a departing employee can become unrecoverable.
ON SPRAWL
Prohibition without an approved alternative produces concealment. Provide tools that meet the need.
Review card statements to find services you did not know existed.