Checking my last day of health coverage - 6 months and counting

I was told my coverage ends on my last day, but the letter says the end of the month. I worked as a dental hygienist before this. I do not want to be surprised by a bill. How did you confirm your end date?

I moved my appointments earlier while coverage was active. It saved me a bill.

Ask HR to confirm the exact date in writing. I also called the insurance company to double-check.