I do now. I had to wait for my "emergency" surgery because we needed permission from the health insurance. I didn't have my wallet with me, or something (maybe I had my wallet but not a physical copy of the card? my memory is a little fuzzy now). I knew who the provider was and they were able to call the insurance with my social security number and get everything cleared up, but it would've been a lot easier for all involved if I'd just had it on me. Especially since I live alone, so it's not like I could just call someone to bring it.