I only use ''You're'' when:
1-It's a semi-formal Letter (I usually use 'You are' but If the letter is to someone on the same professional level, I use it.
2-In online conversations with some respectable strangers or people I know
3-When I try to be a Grammar-n*zi and try to 'correct' people in an argument in TF2 or on Discord...
Also, What do you think about "American" English ?