This is also a regional and venue specific issue. For example, if you visit Las Vegas and hit the strip or stay at a casino, expect to tip practically every human worker you interact with, from the shuttle/Uber driver, to the bellhop holding your bags, to the waitress at the slot machine, to the any restaurant you visit, and everywhere in between. This hooks true for most all resort/vacation areas. However, normal places have tipping pretty much limited to only waiting staff, and typically is 15%-20%. Please don’t tip on credit card readers at places like donut shops and other small stores where your literally just buying something and leaving: it’s just making the problem worse.
Natürlich, aber mit einmal Zigaretten für meine Mitarbeiter. Es ist mir eklig. Immer schwarze Kaffee!