Checking my last day of health coverage - 20 weeks in

I was told my coverage ends on my last day, but the letter says the end of the month. There are 11 people counting on me, so I am trying to be careful. I do not want to be surprised by a bill. How did you confirm your end date?

Keep a copy of any coverage confirmation in case of later disputes.

Dental and vision sometimes end on a different date from medical. Mine did.