> And why is it so hard in Amazon to know if someone is using a service? At one point our manager asked us to shut down a service to see if someone was using it.

Don't collect any usage statistics works. In our org we're switching a lot of smaller services to lambda and using fewer and fewer EC2 instances to do our work. But then, we actually track usage on every service so there's that.

Don't know how long it has been that you've left, but this is no longer an issue. There's a discovery mechanism now that keeps track of all service to service interactions.

Also, that's a strange suggestion, couldn't you have just looked at request count metrics?