When to switch from 'usted' to 'tú'

When to switch from 'usted' to 'tú'
 

Hi all,

I'm wondering when you would generally switch to 2nd sing from the formal usted? In German people who don't know each other are usually addressed in the formal form and by their last name until someone says 'I'm *first name*' and that is taken as an indication to switch to informal. It's usually expected to be the female and/or older person that invites the switch.
Outside a professional setting, people of the same age would use the informal right away.

What are the social rules in Spanish? I'm currently reading a Spanish book for students and I see a lot of 'usted' used with the first name and even within in the family (a child addressing her great grandmother). So I'm just wondering if that is accurate.

Thanks!

Ufff...
I'd like to think it's similar to German (to some degree...) but the conventions and "manners" are getting more and more loose... so the "tuteo" (informal) in Spain becomes prevalent... "no matter what".

Using "usted" could even considered "dated", however, not incorrect at all.

I never called my parents using "usted", yet I know friends of mine who would address them with that "respect"...

Some times older people would say "No me hables de usted, que me hace muy mayor, tutéame..."

At any rate... these are my two cents... (A book could be written about it, but I think using "usted" would not be incorrect in any setting...)

Non-native speakers are at a disadvantage here unless they are intimately knowlegeable about Latin American cultures. As J Pablo wrote, Spain prefers tú. Other countries have not followed suit however, and among Cubans and Colombians, Ud. is very commonly used. Ud. is most commonly used for people you don't know who are older than you.
If you used tú and responded with Ud., it may be advisable to continue with Ud.

This is something you just have to get a feel for as you learn more and more Spanish and especially when you are around native speakers of Spanish. My wife is Cuban and my son-in-law is Mexican from Mexico and we only speak Spanish to each other. Cubans and Mexicans seem to use usted and tu the same. Central Americans use vos a lot. However when the Central Americans come to California and are around Mexican speakers they adapt to this usted and tu deal.

I had a girlfriend from Ecuador and one time she told me that a policeman here in California addressed her with tu. She said it was a big insult to her. That always stuck in my mind. She made it seems as if he had no respect for her.
I would never talk to a policeman using the tu form and I would expect him to address me with usted. If you were going to/for a job interview for example you would of course use usted and visa versa. It's really quite simple but it's still something you need to get a feel for. A proposito/By the way once you know this it is the same idea in both the Italian and French languages.