For city breaks in either Lisbon or Porto, plan a minimum of three days in Portugal. You can always plan day trips to places like Sintra or Cascais if you have extra days.
Taxis are quite cheap everywhere in Portugal, including Lisbon. Your taxi driver might not speak English and there are always surcharges for evening, public holiday, and weekend rides.
Portugal uses the Euro currency and, unlike the rest of Western Europe, cash is still king. Always carry a generous (but not unsafe) amount of cash on you to pay for small items and taxis and to leave a tip at restaurants.
You cannot visit Portugal without trying a pastel de nata, an egg custard pastry with cinnamon and vanilla. Grilled sardines and cod are also delicacies here. In fact, Bacalhau (dried or salted cod) is Portugal’s national dish.