Checking my last day of health coverage - 4 weeks in

I was told my coverage ends on my last day, but the letter says the end of the month. There are 12 people counting on me, so I am trying to be careful. The letter is unclear about dental and vision. Did coverage match what HR said?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

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