Things to be checked:
- Directory structures (recursive, with any attributes and properties)
- Configuration (equiv and partial conf, format specific or generic, with regex)
- Registry (presence of keys, same/diff values etc)
- Services (specific ones by name/pattern, status - running, stopped, autostart etc)
- Scheduled tasks
Yes, you can check some of these with monitoring systems and templates quite effectively (for example services running/not). However, you need to be able to have comprehensive diffs view for things like Directory Structures, Config files etc, which is limited by restricted views of monitoring tools (usually traffic light & short description - as it should be).
You will only run these comprehensive consistency checks on demand, for example after a deployment.
