I stayed in Lisbon for 5 days, so I exchanged my 72-hour pass at the tourist information center and used it. It turned out to be a great decision! Not only does it grant free admission to major tourist attractions like Jerónimos Monastery, Belém Tower, and São Jorge Castle, but it also allows unlimited rides on the subway, trams, and cable cars with just one pass. Lisbon has many hills, so being able to easily take a tram or elevator even for short distances was a real lifesaver physically. I used one of the three days for a day trip to Sintra, and since the round-trip fare for CP (national railway) is also included, I think it offers the best value for money. The system of counting 72 hours from the "time of first use" rather than the date was also efficient and prevented waste. If you're planning to thoroughly explore Lisbon, I definitely recommend it!