When I learnt to use chopsticks I learnt the normal practice at the time: diners used their own chopsticks to pick food from the communal dishes. I read that chopsticks did not touch the lips; I didn't believe it but I carried on as if I did.
When I thought about it, it seemed a distasteful and unhygienic practice. I always use serving chopsticks now, even at home.
What is the general practice?