Good news! CM12 manages client health for you by invoking ccmeval.exe via a scheduled task. By using a scheduled task, ccmeval has no dependency on a healthy CM client. Actually there is one small dependency—ccmeval is configured automatically by the CM12 client, so the client installation has to be healthy at one point to configure the ccmeval cycle. Both ccmeval and SMS Agent Host (the service for CM client agent) perform checks against each other regularly, to ensure that both are configured properly. The client is routinely checked for issues which are reported back to CM, but the problems found are fixed on the fly as well!
If a client component or service fail to repair, that too gets reported back to CM so you can investigate as needed. We'll show you how to make sure clients are healthy.