Wikipedia has this map of tipping customs in restaurants:
This might be useful for those of you who like to do things as they are done customarily.
Me, I am rather skeptical regarding tipping. And it really pisses me off when people expect it or even add it to the bill, like I have experienced it in Chile and the US. If you run a restaurant and you can’t pay your staff a living wage, close the damn restaurant! Or if you know that you need to charge 10% more, amend the menu instead of luring customers with fraudulently low prices.
Also, I don’t quite understand why I, as a poor freelancer earning less than minimal wage should support people with a fun job that even comes with free food. And ain’t nobody never tipping me when I deliver a great translation (which does not come with free food).
No, I reserve tips for cases when I want to. For example when I spend more time than normal at a restaurant, reading a book and smoking a cigar for an hour after I have finished lunch, then I pay extra for the time that I occupied the space. Or when a hairdresser in Brazil or Romania has to communicate with me in a foreign language, then I compensate them for the added stress. Or when a taxi driver helps me carry my bag to the house. Or the guy at the hotel who patiently answers all my questions about where to find this and that.
But if you do run a restaurant or a shop and want tips, I recommend that you put up a jar for all tips for the whole crew. Otherwise, the practice is rather discriminatory, with young people receiving more tips than older people, beautiful people more than less beautiful people and big-breasted women more than their lesser endowed but probably equally hard-working colleagues. (Yes, there is a study on that.)