I speak Italian, German, and French. The rules for when to use the formal address are complex, differ from language to language, and are changing every day.

The formal address is largely deferential. You invoke it both to imply status and emotional/social distance. That’s the common thread I noticed in these three languages. Italians being more informal, you end up using the informal address with a lot more people; German society is more formal and you keep your distance even from people (like coworkers) that you have known for a long time.

But I would say that in all three of these languages, formality is becoming more and more infrequent. I think this is illustrated very well by the way media and web sites address users and visitors, which is going quickly from the formal form to the informal.

There seems to be also an influence from English, which has no formal address. I notice that in dubbed media, like movies and TV shows, that frequently don’t really know what to do with the different forms available in the context of source material that doesn’t have it. Sometimes it’s amusing, like the scene where Captain America (I think) used the informal address to his superiors, which would have been absolutely insulting for a military officer, akin to calling them “bro” in English.