We use it for servers, domain controllers, application servers, Oracle servers, SQL servers, as well as network devices, like routers. For PCs that are used for services such as credit cards and ATMs, we usually do a vulnerability assessment, including Windows Servers, Linux servers, SQL servers, and database servers. We scan everything except basic PCs because it would require a lot of time to check all those reports. Our system administrators use another solution to check regular PCs for Windows and MS updates.
We're checking things every month. We created a schedule and it checks automatically. From time to time, we'll use it to check things if something unusual has happened. For example, if a stranger was on a computer, we'll check if is there a vulnerability there.
We also use it to prepare reports when the agency asks for them.