We'd typically look at everything, and you're absolutely right. Dev environments are often also poorly managed and you can find lots of resources nobody knows who are using.
The most important thing tends to be to make it possible to run services in isolation so devs can test individual services on their own machines. Then you'll end up with much more time-limited need to spin up larger environments for integration tests etc.
The most important part, though, tends to be to ensure you have a system to keep track of what is running and who is currently using it.