I am still learning my eero's and find my self constantly in the app.  I have left the white lights on the eeros since that my only way of knowing its OK other than it working.  But a device could fail and clients would move to another device and I would knot know.  I think if a device is off line for 5 minutes or in "red" state an email from eero could be sent telling me it's off line.  I get this for my thermostat on the wall.    I am aware they turn RED in the app, or consider having the app alert me on IOS, and not have an email.  This would work also.  Thanks!!