10% is customary here in the UK, but then we do have minimum wage; AFAIK tips are tips. When I was last in NYC the minimum was 12.5%, and that wasn't all that

10% is customary here in the UK, but then we do have minimum wage; AFAIK tips are tips. When I was last in NYC the minimum was 12.5%, and that wasn't all that long ago - I was impressed that the bill included tip calculations, but what really annoyed me was the "would you like the change" thing.