Best practices for monitor of remote devices?

I can't seem to find what I'm looking for in the documentation so I figured I might as well ask here... what're the best practices for the monitoring of remote devices?

If I have a bunch of satellite offices (and equipment in which I want to monitor) I presume the ideal situation is to have a collection agent at each site. If that's not doable, or I just want to monitor a one object, would there be any issues monitoring it via a remote agent?

When it comes to Avamar I notice that the "collector" (maybe I need to be searching for the term collector in the documentation other than agent) needs to be in the same timezone as the Avamar server itself. Does that mean that both the Avamar server and the agent's host's time settings need to be configured for the time zone? Or that they need to be physically located within the same zone?

Also, since I can't seem to find it either, what's the best practice for # of devices monitored per agent?

Thanks!