How many days should you spend in Porto?
Give Porto at least enough time for the river, food, port lodges and slower northern rhythm to register. It can be seen quickly, but the better version is not just a one-night photo stop.
Answer
Porto is smaller than Lisbon in the ways visitors notice first, but that does not mean it should be rushed. The city works through atmosphere: steep streets, heavy stone, river light, tiled churches, long meals and the slower pull of the north. Two full days can give a strong taste; more time makes sense if you want the Douro, Braga, Guimarães or a gentler pace. The mistake is treating Porto as a pause between Lisbon and the next transfer. It is one of the places where Portugal gets moodier and more textured. Give it a little space and it often becomes more than the pretty second city.