Americans are used to tipping in restaurants and for certain services, but when traveling abroad we are easily confused by what is customary and considerate. Every destination varies in tipping practices, but in Europe you can generally consider:
Tour directors: $10-15 per day, per person is customary and reasonable depending upon the level of service. Soirée Travel Liaisons are the people who travel with you on your customized tour over the course of several days or weeks. They generally work 12-16 hours a day for 10-14 days in a row, often behind the scenes in addition to the hours they spend with you. They function as a concierge, problem-solver, logistics coordinator, entertainment planner, and host. They are usually experts in their field, and have years of experience leading travel.
Private guides: guides in most of Europe are licensed professionals. They have earned their credentials in a program as rigorous and lengthy as a college degree program, and they are experts in their field. They usually charge corresponding guide fees, but tips are both considerate and appreciated. Unless you have spent enough time or days with your guide to develop a rapport and you want to tip more heavily, 5-10 Euros or GBP per person/couple is reasonable.
Group guides: Joining a group tour for the morning? Five to ten Euros or GBPs is reasonable depending upon the quality of the tour.
Free walking tour guides: €10-20 or £7-18 is reasonable depending upon the duration and quality of the tour.
Waiters/Waitresses: these folks do not work for tips but are provided a living wage. Still, tipping to show appreciation for good service is customary even among locals. Ten to fifteen percent may be reasonable in Paris and a solid 15% in London. In Italy and Spain 10% may be too much, but a few coins or rounding up the bill shows respect and consideration. Keep in mind that in most European destinations, tips must be left in cash at the table and are generally shared among the service staff.
Private drivers: whether you have a private car or are on a multi-day trip with your group, it is appropriate to tip the driver for good service. €3-5 or £2-4 per day, per person is reasonable.
Taxis: it is general practice to round up the taxi fare to the nearest Euro or Great British Pound (GBP). For instance, €7.30 might become €8 or £22.90 might become €23.
Porters/bellhops: €2 or £1.50 per bag, per service
Concierges: generally a small tip is appropriate and appreciated if the concierge has provided any special service to you such as booking tickets or making dinner reservations. Use your discretion, but €5-10 or £5-10 is reasonable.