Cultural differences ... using first names of others husband

Here, perhaps it's not really a formality or rule. In most cases, people are not offended either way, it seems. However, my Japanese parents would care about name usage - it is about familiarity like you said - a courtesy you give to the other person. I remember when I was a kid, my long time Japanese friend had a birthday party and all her non-Japanese school friends called her mother by her first name. Because of that, I called my friend's mother by her first name too. My mother was there and oh I got a yelling for that. She said I was so disrespectful for calling a friend's mother by their first name - I never did that again. Not to a Japanese adult anyway . Depends on the culture I guess.

I try not to unless it is someone I know well. I have a best friend named Joan and her husband is Bob. We have known each other since our kids were little. We have all been on trips together and know each other's kids and relatives. For casual acquaintances, I say husband or wife. I never friend children on social media even if I know them. I think it is wise not to do that. When they are older, I have friended them but never their kids. I only ever friended one kid. She was eight years old posing as a grown woman. I alerted the grandmother but she said the kid's father allowed it. I friended her to keep an eye on her to make sure she did not have groomer friends who wanted to meet her. It is so dangerous. She used a photo of her own gorgeous self as a profile and cover photo.

I perfer to call a person by their name. Honestly, I don't really know of an instance where I'd have to have to use someone's title. Hell, neighbors I don't really know, would ask me how my husband, George, was doing as well as offer their help when he was in the hospital from a stroke. He's home now and we're getting back to normal. But, people would always ask me 'how's George' not 'how's your husband?' But then I think that's sutheren logic and hospiality.

Here first names are commonly used

Australia is pretty casual and first names are mostly used. Even our doctors are now usually addressed by their first names.

it depends. no rules anymore, which isn't always good. we rather use formal you.

If I am given a first name, yes, to the point it is hard to remember last names of some coworkers. There are also conventions in work setting where someone becomes known by their last initial, such as Mrs. K our Librarian. Her first name is Lori, but I do not think of that. Within the school one or two people I get confused when someone mentions their first name. They are on a different level than I am. With adults, I am okay with using my first name, but I call myself Echola--my last name--to the kids, because my first name is pretty common--Heather and we have more than one Heather at school. Others (mistakenly) think last names are too hard for kids, they are wrong. It is called respect.

Same here, we ask how is your Dad, your husband or your wife, first name is only in the family or very close friends. I do not like when people ask about my husband using his first name, if they are friends it is okay, but people I barely know is wrong.

It really depends on how close we are to people, Sometimes if we just know them then they are always referred to as Mr or Mrs and their last name, If they turn out to become close friends then everyone uses their first names,

I use the first name with my school and college mates and those who are younger to me.

It depends actually. We addressed by first name if we are close with the person. If not, we use the common 'wife', 'husband', 'parents'... So it's kinda differentiate in what kind of relationship you have with the person.

Here in the US it's common practice to call people by their first names. Have a good week.