When would be appropriate to use formal and informal second person?
For context, I'm planning to speak mostly with my Mexican family members, many that I'll be meeting for the first time or for the first time in many years. Most of them are older than me (I have one younger brother who speaks mostly Spanish). Would it be better to speak formally to the older family members, or informally because they're family?
Would you start formally with strangers (esp. those who are older) and then at some point be able to drop formality as you become closer to people, or as they express to you that it's okay (similar to Korean and Japanese)?
