Tipping in Argentina and Buenos Aires is not expected, but it is always appreciated. In many restaurants, a table charge or ‘cubierta’ of $5 is added onto the bill, but this is not considered a gratuity. A 10% tip, or ‘propina’, is appreciated, but not obligatory. In smaller cafes or bars, a peso or two is the usual tip. Many locals, however, will tell you not to tip unless it is a place that you plan on frequenting.
Taxi drivers don’t expect a tip, but most passengers will round up the fares. It is typical to tip drivers of hired cars 10%, as well as tour guides. For other services, like delivery or spa treatments, a few pesos ($4-5) is the customary tip. In hotels, bellhops, doormen, maids, and waiters expect a tip of a few pesos as well; the same is true for barbers and beauticians. However, they are not required or expected for the doormen of apartment or office buildings.
In short, if you’re satisfied with your service, by all means leave a tip, but there’s no need to make it excessive — ten percent will do just fine.