You should know where the nearest Emergency Room to where your live. Likewise, you should know where is the closest Urgent Care.
Why?
Insurance dollars mispent translates to lowered benefits or salary. It could also lead to staff reductions making everyone's job harder. We have earned terrific benefits, but we should also be the ones taking care they are not wasted. The ER costs up to 10 times higher than an Urgent Care for the same non-life-threatening emergency.
When you believe there is a life-threatening medical issue then there should be absolutely no question that you should go to the ER. If you question the medical emergency and are not sure what is going on, then you should probably go also. If it is a non-life threatening emergency and you know things will be OK, then you should probably go to the nearest urgent care.
Facitilites switch between being in network and out of network, so it is helpful to check online with MMO or through their mobile app which nearby facilities you should use.
New January 2020 - Non Emergency visits to the emergency room will have a $100 co-pay either in network or out of network. COMPARE ER - URGENT CARE - CONVENIENCE CLINIC (pdf) to see what kinds of issues are considered emergencies by insurance companies.