My aunt and uncle have the same Apple ID. I think they need separate ones, do they?

I've told them to get separate ones in the event that they need to back up their phones or get new ones. Don't they need separate ones? They hardly back up their phones or hook up their iPhones to the computer.

My parents share an apple account and it seems to be fine.

If they want to share the same exact apps and pics and music, who cares? Best luck.