Hi Megan,
Great questions. I’ll go through the different scenarios one by one. At restaurants, 10% service is always included in the bill. It’s either a separate line item called “servicio” or is included in the menu prices (the menu will usually say this). Servers really don’t expect more than the 10%, but we like to give a little extra for exemplary service or if the food was really inexpensive and the 10% seems just too low. For housekeeping and baggage assistance, wages are low in Costa Rica especially compared to the relatively high cost of living so we like to leave about the same as we would in the US- a dollar or 2 a day for housekeeping and $1 a bag for help with baggage. Of course, everyone has a different opinion on this so keep in mind that some people do more, others less. You didn’t mention taxi drivers- they don’t really expect a tip but we usually round up or give a dollar or two more depending on how helpful they were.