A 7-hour layover is often considered the "sweet spot" for travelers—it is long enough to leave the airport and see a bit of the city, but short enough that you don't need a hotel room. If you decide to leave the airport, you should first subtract about 3.5 hours for transit and security: roughly 1 hour for deplaning and travel to the city center, and 2.5 hours to get back, clear security, and reach your gate. This leaves you with a solid 3 to 3.5 hours of exploration time. In cities with fast airport-to-city rail links like London (Heathrow Express), Amsterdam (Schiphol Rail), or Tokyo (Narita Express), you can easily enjoy a nice meal, visit a major museum, or walk through a historic district. If you prefer to stay at the airport, 7 hours is perfect for booking a day pass to a premium lounge, where you can shower, eat, and work in comfort. Many large hubs also offer on-site amenities like "Minute Suites" for a nap, movie theaters (Seoul Incheon), or even swimming pools (Singapore Changi). If you are in a city that offers it, look for a "transit tour" organized by the airport or local tourism board, which is specifically designed to get you back in time for your connecting flight without the stress of navigating a new city on your own.