As in most of Europe, tipping is voluntary, and the locals differ in how much they tip, if they tip at all. Some say 10 percent, some say more, or less—it's really up to you. Don't feel like you have to tip, but waiters will probably be glad if you show appreciation of their service. There is no need to tip taxi drivers or hotel staff. If you are visiting Oslo before Christmas, be sure to make reservations for all your lunch and dinner outings, as eateries are fully booked the last weeks before Christmas. Also, remember that on Sundays most shops are closed.