Is it common to be on family plans for cell phones?

Not sure if this is the right sub. My husband had been single for over 10 years. Dating, but nothing serious and did not share bills or accounts.

I’m on my parent’s old cell phone plan after friends and family got popular. My parents passed, but it’s me, my son, my brother, SIL and her dad. We can add my husband and I send my brother extra $.

My husband insist this is weird, but I think it’s common. Most people I know do the same. Just want to know what the majority of people in this sub do?